Answered in original thread.
http://www.teamfortress.tv/post/470219/yet-another-quot-should-i-buy-this-or-this-quot

Is it possible to move posts in this forum? I'm going to post here since everything I'm refering to is here aswell and OP's links aren't in the PC Build Thread.

1. Yes, your CPU and GPU are mismatched for everything except TF2/streaming. TF2 puts almost no load on the GPU, you could even get away with the iGPU integrated in the i5-4570. All the work for streaming is done by the CPU, absolutely nothing by the GPU. Don't ask why, it's difficult to explain. So even though your GPU is low end, it's enough for what you're doing and upgrading it won't help at all.

2. No, the GT 740 is not a huge upgrade. Apart from the fact that upgrading your GPU won't do anything (see 1.) it's barely faster than the 550 Ti. At that price you could indeed get a 750 Ti (see #8) which is twice as fast.
Then there's the difference between VRAM size and GPU speed. They are not related. The same applies to RAM, HDDs, SSDs and even motor vehicles. A truck is definitely larger than a car, does that mean it's faster? I think you know the answer to that question.
Now why would you need larger VRAM? For the pretties. Higher resolution (e.g. 1440p or even 4K instead of 1080p), Antialiasing, Anisotropic Filtering, etc. all these things increase VRAM usage. If you don't have enough VRAM for 16x AA you'll have to live with 8x AA. But all these things also take time to compute. More than 1GB on a low end card like the 550 Ti or 740 doesn't make sense because even though you could crank up the settings to use more than 1 or 2, maybe even close to 4GB the card just doesn't have the performance. You'd be getting very "cinematic" 5fps. On "normal" cards VRAM increases the higher up you go on the food chain, which is only logical.
GTX 960 2GB, 970/980 4GB, 980 Ti 6GB.
Now why do 2 and 4GB versions of the 740 exist? To make money. They are mostly used in pre-builts and when you don't even mention the GPU model "4GB nVidia™ Graphics Card" sells a lot better than "1GB nVidia™ Graphics Card". It's not any faster, but that doesn't matter.
As to why the GTX 980 is 500$, it's simple: It's very fast.
Against the 550 Ti the graphs just look ridiculous.
http://anandtech.com/bench/product/1133?vs=1351
The 750 Ti is twice as fast as the 550 Ti and still can't hold a candle to it.
http://anandtech.com/bench/product/1130?vs=1351
I'll leave the last question unanswered since you shouldn't go by VRAM size and you don't need a new GPU anyway.

3. No, the FX-8350 isn't exactly better than the i5-4570. It's complicated, basically it is slightly better for streaming, but you'd be getting lower fps in TF2. For now I'm not going to explain why.
It also won't fit in your motherboard so you'd have to buy a new one aswell. Spending >200$ for a tiny difference and less fps in TF2, both while you're streaming and while you're not, is just a waste of money.
Now for FX vs i7. I have a less technical analogy than #9's.
Imagine two persons. Person A(MD) takes 4.0 steps per second, person I(intel) takes only 3.2 steps per second.
Which person is faster? Trick question, person I's steps are twice as long. For the i7 which has sort of 8 cores, similar, but not quite like the FX-8350 has sort of 8 cores (difficult, don't ask), it's not even close. With the i5 it's not as easy since it has only 4 cores. It's complicated but the break points is ~6 threads. Less and the i5 is definitely faster, more and the FX-8350 might be faster.

4. The FX-8350 is 3 years old. You don't buy 3 year old CPUs. The only CPUs that fit in your motherboard are the same architecture as your current CPU and there aren't any i5s with significantly higher clockrates. Spending >200$ on an i5-4690 (3.5 vs your 3.2GHz) for <10% improvement isn't worth it. i7s really are your only option. If you live near a microcenter and can afford it you could pick up an i7-4790K for 280$. You're looking at a 25% improvement just through the higher clockrates. When streaming Hyperthreading comes into play and the difference will be a lot greater.
If that's not possible you could get a Xeon E3-1231 v3. It's basically an i7 without the iGPU, which you don't need since you have a dedicated GPU already, so why pay 50$ for something you won't use? It's clockrates aren't much higher so in TF2 alone the difference won't be much, but for streaming it should improve performance significantly.

EDIT: fixed typo.
EDIT: another fix.

#564
I'm not a fan of the case but I don't have the time to look into alternatives atm.

For Cooler, RAM, SSD, HDD see #562, same reasons.

PSU: The CX430 is a budget PSU, it's not great but fine if you're on a budget. In this case it's the wrong choice for 2 reasons:
1. When you made that partlist it wasn't on sale. At that price there are better PSUs.
2. Even though it's on sale now, I still wouldn't get it. My rule is 5-10% of the budget for the PSU. If you're below that you're skimping out, if you're above that the PSU is either overpriced, oversized or overkill (possibly all three). In your case the range is 65-130$.
The Antec Neo Eco 620W at 70$ fits perfectly as "low end" option. That's one of the implications of the 5% rule. Low end for a 1300$ build means "low end Seasonic or comparable".
If you want modularity you'll have to shell out another 10$ for the Antec HCG-400M. It's the same platform.
If you might want to go SLI (not possible with the Z170-P D3, although I'd recommend a more powerful single GPU anyway) or simply want a fully modular PSU there's the Seasonic M12II 520W for another 5$ more. Again the exact same platform as the Antec HCG-520M but 1$ more gets you a fully instead of semi-modular PSU.

http://ca.pcpartpicker.com/p/RgCwQ7

Now about Haswell Refresh vs Skylake. In terms of motherboards it's still looking pretty dire. The Z170-P D3 specifically doesn't really offer anything over Z87/Z97. It's still using DDR3 and doesn't even have SLI support like the >50$ cheaper Z87-A, so unless you have some very specific needs that Z170 can fulfill, it's just not a very good deal.
Don't get me wrong, Z170 is clearly better than even Z97, but do you even need what Z97 has to offer over Z87? Do you need an M.2 slot? Trading SLI support and 50$ for USB 3.1 just doesn't seem right.

Specifically 6600K vs 4690K. Skylake isn't that much faster so it comes down to overclocking. There's not enough data yet to reliably say where the 6600K will end up and how much spread there is in the silicon lottery.
Skylake has the advantage of higher efficiency/lower power consumption but beyond that we don't know anything for sure yet.
Does it use the Haswell, Haswell-Refresh/Devil's Canyon or an entirely new thermal paste? We don't know.
How well does it handle Voltage? We don't know.
What clockrates can you expect with a midrange cooler like the 212 Evo or T40-TB? We don't know. Most tests use a beefy high end air coolers or aios in jet engine mode, some of the more overclocking oriented reviews even use custom water loops, specifically to remove all thermal limitations. Of course you can get a PH-TC14PE or NH-D14 but that's another 50$.

http://ca.pcpartpicker.com/p/njqdQ7

At some point you've got to ask yourself if 95% of the CPU power for 100-150$ less isn't the better idea. Especially if you can put that money towards a 970 or 390.

http://ca.pcpartpicker.com/p/8cPfBm

I could easily get it below 1300$, but I couldn't resist the number.

What I'd do is wait. Wait and see if the motherboard situation changes. Wait for the non-K Skylake CPUs and the other chipsets. If they overclock decently you might be able to get the new Z170 features and the same performance as the 4690K oc'd at the same price. If the mobo manufacturers figure out a way for non-Z overclocking again you might even get it at a lower price.

I know this is pretty much the opposite of what I recommended in #562 but that's the Canadian prices.
Getting a Z87 mobo at a lower price than all except one H97 mobo (with the difference being 7$) is simply a game changer.

#565
Well it means that if you get a Z87-A that still runs a 1+ year old BIOS/UEFI the i5-4590K might not work. But I wouldn't recommend it if there was a chance that you couldn't use it. The Z87-A among others mobos has this neat little feature: You can update the BIOS without a CPU or RAM installed. You just need a USB stick.
Here's a guide.
http://rog.asus.com/339292014/labels/guides/guide-update-your-maximus-vi-or-asus-z87-motherboard-with-usb-bios-flashback-for-devils-canyon-4790k-4690k-cpus/

Budget?

Intel doesn't support overclocking on anything but Z-series chipsets. Motherboard manufacturers have found ways around it, but if you can avoid it there's no need to "risk" lower overclocks by that.

In theory if there is non-Z overclocking for Skylake aswell the non-K CPUs might be fairly good value since they are supposed to be overclockable via BCLK. You'd also get DDR4 and a newer chipset.
If you don't care about those things you could buy now. You could wait for price drops but there is a nice deal for the Z87-A right now and I don't think it's going to get much better than that.
The H97M-Anniversary is the cheapest mobo I'd consider and it's 51.98$. 7.02$ won't break your budget and you get Z87 -> full overclocking support.
RAM: It shouldn't make much of a difference but dual channel RAM is recommended.
SSD: Don't buy the V300. Kingston pulled some bullshit there, replaced the NAND mid-series, which halved the performance. And they didn't bother to tell anyone.
1. That's a dick move.
2. Thanks to that the 850 Evo is now more than twice as fast. Definitely worth +15$.
HDD: The Seagate Barracuda is a bit cheaper and slightly faster than the WD Blue.
GPU: For low-mid settings you could go far lower, even a 260X should be enough, but just to have a bit more power in other games I'd go for the 270/270X. But as it turns out there are a few 285s for the same price. And guess what, the 380 is just a rebranded 285. God this feels awesome.
Case: I find the lack of dust filters disturbing. There's also no HDD vibration dampening, making the 200R a bit loud. For 50$ it's just meh.
Let's take it up a notch, have a look at the Thermaltake V41:

http://www.tweaktown.com/reviews/6853/thermaltake-core-v41-mid-tower-chassis-review/index7.html
A little price drop and 20$ MIR later and we're at 59.99$. Nice.

PSU: I thought about wether I should recommend a budget PSU (EVGA 500B at 35$) or a higher quality one, but then I realised you can have both. Antec Neo Eco 620W. Same platform, though not modular, but it's only 40$ right now. If you want modularity definitely go for the M12II 520W, at that price nothing comes close in terms of performance and most PSUs are just semi-modular, too.

I threw in a better CPU cooler aswell.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor ($224.99 @ SuperBiiz)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($25.98 @ OutletPC)
Motherboard: Asus Z87-A (NFC Express Edition) ATX LGA1150 Motherboard ($59.00 @ Newegg)
Memory: Pareema 8GB (2 x 4GB) DDR3-1600 Memory ($42.49 @ Newegg)
Storage: Samsung 850 EVO-Series 120GB 2.5" Solid State Drive ($63.99 @ Amazon)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($43.99 @ SuperBiiz)
Video Card: PowerColor Radeon R9 285 2GB TurboDuo Video Card ($153.98 @ Newegg)
Case: Thermaltake Core V41 ATX Mid Tower Case ($59.99 @ Newegg)
Power Supply: Antec Neo Eco 620W 80+ Bronze Certified ATX Power Supply ($39.99 @ Newegg)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($13.99 @ SuperBiiz)
Total: $728.39
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-08-09 17:03 EDT-0400

That was the most satisfying build in a long time. It was like standing in a bakery, contemplating the dilemma of not being able to have the cake and eat it too and then seeing a sign "2 cakes for the price of 1".

For this build I'm even dropping my "new CPUs next month" disclaimer.
I could definitely go lower if you have, but it'd be a shame.
You could just aswell go up again, Seasonic M12II 520W again, possibly a 250GB instead 120GB.

We had a nice chat via steam.
Let's see if any of this changes when he comes back in three weeks.

This is what we started with:
http://pcpartpicker.com/user/decderify/saved/6LvQzy

This is the result:
PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i7-4790K 4.0GHz Quad-Core Processor ($323.99 @ SuperBiiz)
CPU Cooler: Phanteks PH-TC14PE_RD 78.1 CFM CPU Cooler ($64.99 @ Newegg)
Motherboard: Asus Z87-A (NFC Express Edition) ATX LGA1150 Motherboard ($59.00 @ Newegg)
Memory: Kingston HyperX Fury Black 8GB (2 x 4GB) DDR3-1866 Memory ($41.99 @ SuperBiiz)
Storage: Samsung 850 EVO-Series 250GB 2.5" Solid State Drive ($97.89 @ OutletPC)
Video Card: MSI Radeon R9 390 8GB Video Card ($324.98 @ SuperBiiz)
Case: Fractal Design Define R5 (Black) ATX Mid Tower Case ($94.99 @ NCIX US)
Power Supply: EVGA SuperNOVA G2 550W 80+ Gold Certified Fully-Modular ATX Power Supply ($69.99 @ Newegg)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($13.99 @ SuperBiiz)
Operating System: Microsoft Windows 10 Home OEM (64-bit) ($91.75 @ OutletPC)
Total: $1183.56
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-08-09 13:55 EDT-0400

CPU unchanged.
Cooler: Here's my rant about all in one liquid coolers. The Phanteks PH-TC14PE is very good and fairly cheap for a high end air cooler. A bit to back it up:

http://www.hitechlegion.com/images/cooling/corh100i/b2.jpg

Only on "performance" setting does the H100i even beat it. And guess how? The standard MO of all aios: jet engine mode.

http://www.hitechlegion.com/reviews/cooling/liquid/33165-corsair-h100i?showall=&start=3
So with the exception of the H100i in jet engine mode the Phantek is both cooler and quieter.
Also: Pretty colours.

Mobo: The Z87-A isn't even half the price of the Z97-Gaming 5 and still has SLI support, it's hard to beat that. Praise the Z87 markdowns.
RAM: 8GB should be fine, you can upgrade later if you should actually need it. There's nothing inherently wrong with Corsair RAM (at least I hope not, the Vengeance series used to have to highest RMA rates across all brands) but it tends to be overpriced. Replaced with faster and cheaper RAM.
SSD: The 850 Evo 250GB is cheaper than the 840 Evo 120GB. Faster and more than twice the capacity, a no brainer.
GPU: He told me he had actually decided on the 390 already but forgot to save it.
Case: The Define R5 is simply an awesome case.
PSU: Apparently reddit talked him into the G2 750W. For a 460W build. Yeah I don't think so, those 37$ would be wasted.

I wouldn't use windows 10 for now, but until he gets back this might've changed.

#10
To make sure everyone believes the Corsair RM series is as bad as I said and because I hate it with a passion and because it's an easy target (like taking candy from a baby):
https://www.reddit.com/r/pcmasterrace/comments/3gaz7m/died_before_it_had_its_chance_psu_had_a_short_and/
Corsair RM750 shorted out on the first attempted boot and fried all components.
300$+ for a EVGA 970? Literally gone up in smoke.
You payed 120$ for the privilege of frying your brand new build. #JustCorsairThings

I'm deeply saddened to see what Corsair has become. They used to sell well-performing Seasonic units at decent prices but now... and it's not just PSUs.
Somewhere along the way they decided to sell lower quality at higher prices. "Gaming" branding does not justify a 100% markup and definitely doesn't excuse skimping on quality control and I will keep calling them out on that.
I choose to believe that there isn't any QC on the RM series, because if a PSU that kills your components passed I really don't want to see what happens when a unit fails the test.

Could someone move this to hardware? Do mods even exist here?

I'm not sure if I got all of this so correct me if I'm wrong.
Your CPU sits at 30°C idle? That's normal.
When the there's load on the CPU the temperature spikes? That's normal aswell.
Higher load -> higher temperature, even while browsing there will be load spikes for example scrolling is basically no load, whereas to load a website the CPU will go balls to the wall so it's finished within a second and then clock down again. The heat produced will heat up the CPU almost instantaneously and slowly dissipate again. Even with a constant load the temps will spike at first and then go down a bit again because the cooler needs a few seconds to rev up for three reasons.
1. There's mechanical aspect. Doubling the rpm instantly just isn't a good idea.
2. It only reacts to the temps, it can't them so it'll always lag behind.
3. The reaction is actually delayed on purpose. Imagine the temps spiking from 30°C to 50°C every few seconds with the cooler reacting instantly. quiet -> jet engine -> quiet -> jet engine. Very calming and enjoyable.

Now those 60°C were indeed fine. 97°C aren't. If you didn't remove the old thermal paste then that's your problem.
Regarding thermal paste less is indeed more. You want just enough to fill the irregularities (otherwise filled with air, which is very good at isolating) in both the IHS' and coolers' metal surface to get full contact across the whole surface, but not any more than that. If there's so much thermal paste that the heat has to go through it even where the metals would be touching if there was less, it'll degrade performance. This is what you're seeing right now.

With the pea method if after you've secured the cooler you can just barely see the TP in the middle of the sides, but not across the full length, not at the edges, then you've done it right. A bit less is fine too but you obviously can't see anything in that case so you might have to remove the cooler and check if you're not sure and then start over again.

Which thermal paste are you going to use?

I think you missunderstood.

If you want more than 2*140mm heatsinks you can't fit them on top of the CPU anymore. More than two in a row would block the RAM slots, more than 140mm would block PCIe slots and wouldn't fit into 99% of all cases height wise.

So in that case you'd have to put it somewhere else and to transport the heat you need water.
But since there are no 200mm aios you'd have to buy custom watercooling parts, which means you're looking at 300$+.
1*200mm isn't even better 2*140mm so it's definitely not worth it.

If you absolutely "need" a quieter and cooler setup than what the best air coolers can provide you don't have any options except watercooling. But be prepared to pay through your nose.

tl;dr
2*140mm air >= 1*200mm water and far cheaper
>=2*200mm water > 2*140mm air, but 300-500$ >>> 90$

Short answer: They're never worth it.

Long answer: If we're talking about those all in ones it's simply impossible for them to be better than a comparable air cooler.
Sound: The aio must be louder because the pump adds noise.
Price: The aio must be more expensive because the pump and tubes add cost.
Cooling: Thermodynamics 101. Heat flows from hotter to cooler places. So for the heat to go from the CPU block into the water then into the radiator and then into the air each must be hotter than the next one. By eliminating water as a step an air cooler saves a few degrees. Or in other words, the water actually adds temperature.

Now all of this is assuming that both the aio and the air cooler have similar fans and surface area. If you swap the fans on the aio you could obviously do the same on the air cooler so this changes nothing, but surface area can. This is the reason why watercooling can be quieter and cooler. If you're only using a dual radiator you don't get any advantage over a dual tower heatsink, you're just spending money, performance and noise on moving the heat to a different place. It only gets interesting when that enables you to get more surface area for cooling. For example in a mini-ITX case where you can't fit a big air cooler. Or if want to go beyond two fans. Triple tower heatsinks don't exist, they'd be too large, triple and even quad radiators exist though. There's even 200mm radiators, a size that's impossible for a heatsink directly on top of a CPU. And this is where the fun starts. With a triple or quad radiator you can get better cooling aswell as lower noise because even at slower fanspeeds the higher surface area still outweighs temperature difference the additonal step in the heat flow (water) added. But apart from some pre-packaged systems around 150-200$ we're talking about customs loops north of 300$. Such things are usually done more for the sake of the GPU(s) rather than the CPU. High end GPUs produce far more heat than CPUs (300W vs 100W) and with their smaller fans and maybe another GPU in SLI/Crossfire obscuring their intakes they benefit far more. For GPUs heat dissipation is the limiting factor, for CPUs getting the heat from the CPU into the CPU block is actually far harder. GPUs are very large chips (Titan X/980 Ti 601mm², Fury (X) 596mm²) and heat fairly evenly, whereas desktop CPUs are small (i5/i7-4xxx just 177mm²) with the actual cores being small hotspots and very hard to cool. On Ivy Bridge, Haswell and now Skylake Intel further amplified the issue by using thermal paste and a larger gap between the die and the IHS instead of soldering them together. Removing the IHS and putting a CPU waterblock directly on top of the die is actually a thing because of this. The more "conservative" method is just delidding, scraping off the epoxy glue to narrow the gap, cleaning and applying new thermal paste and then putting the lid back on.

Now some data to back all of this up:

http://imagescdn.tweaktown.com/content/6/3/6313_29_noctua_nh_d15_cpu_cooler_review.png

Notice how none of those aios beat the NH-D15 by more than 2°C.
Since the NH-D15 is 90$ and all of the aios are 100$ or more you should already be asking yourself if that's really worth it.
But here comes the real kicker: That performance was bought by the cost of sounding like jet engines.

http://imagescdn.tweaktown.com/content/6/3/6313_31_noctua_nh_d15_cpu_cooler_review.png

Keep in mind that+10dB sound about twice as loud so those aios are 5 to 10 times as loud as the NH-D15.
Wait, what's that, the Alphacool Nexxxos Cool Answer 240D5/UT is cooler than the NH-D15 and only 1dB louder. See, there are decent aios!
Lolnope.
That's a 300$ kit of custom watercooling parts. You just have to add another radiator and for barely 400$ you can beat the 90$ NH-D15 in both cooling and loudness.

If you can assemble a custom water cooling loop without flooding your pc you can delid your CPU without bricking it. And delidding sets you back just 10-15$ while reducing the core temperatures by 10-15°C.

I guess it's a bit long but I wanted to make my point.

That's not how it works.

Your first try was the H110 which isn't an air cooler.
Second was the H60 which is neither high performance nor an air cooler.
Third was the 212 Evo which isn't high performance.
And replacing the fan with a worse fan isn't going to help.

Since you have ignored every single piece of advice I've given you so far, I'm calling it quits.
You obviously don't want any help, you just want "OMG BEST BUILD EVA!!11!111!!"-type confirmation.
You won't get that here, especially not by posting mediocre builds.

EDIT:

Before I tell you why that's a terrible idea, amuse me: Which fans?

You wouldn't call the H60 an air cooler though.

Ah yes, the most difficult decision.
The reference GPU, stock cooler, not overclocked, 380$ or
a custom design with a better cooler and overclocked for 340$.
Surely the slower, hotter and more expensive GPU must be the right choice?

And that build, oh god.
The H110 is bad idea because it's noisy and more expensive than similar or better performing air coolers.
The H60 is a bad idea for the same reasons and it will crumble very fast once you up the voltage on a non-delidded 4790K.

What did I say about the mobo?

Ah yes, overpriced Corsair cases.

A 750W PSU for a 88W CPU and a 145W GPU?

Last but not least, the masterpiece.
Buying a 200mm fan and a case that doesn't support 200mm fans.

Even ignoring that the R9 390 is faster and slightly cheaper I can throw together a far better build.
200$ cheaper, not even counting the H60 and still SLI capable.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i7-4790K 4.0GHz Quad-Core Processor ($323.99 @ SuperBiiz)
CPU Cooler: Phanteks PH-TC14PE 78.1 CFM CPU Cooler ($64.99 @ Newegg)
Motherboard: Asus Z87-A ATX LGA1150 Motherboard ($72.99 @ NCIX US)
Memory: Kingston HyperX Fury Black 8GB (2 x 4GB) DDR3-1866 Memory ($41.99 @ SuperBiiz)
Video Card: MSI GeForce GTX 970 4GB Twin Frozr V Video Card ($333.49 @ SuperBiiz)
Case: Enermax ECA3310A-B ATX Mid Tower Case ($54.99 @ Newegg)
Power Supply: EVGA SuperNOVA G2 550W 80+ Gold Certified Fully-Modular ATX Power Supply ($69.99 @ Newegg)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($13.99 @ SuperBiiz)
Total: $976.42
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-08-07 19:30 EDT-0400

Not streaming:
i5-3570K if you're willing to overclock.
i5-2500K/i5-2550K could possibly be better if you're not delidding.

It's not exactly a build question, but I think this has become the "general pc hardware" thread anyway.

What are your settings (especially voltage) and temps? Barely and reasonable are subjective.
For Haswell I'd say Vcore 1.4V and Vring 1.3V, VRIN somewhere around 2.2-2.3V but I wouldn't go above Vcore + 0.6V anway.
It should be able to handle 1.45V, 1.35V and 2.4V but it might spike a bit so better safe than sorry. The killzone with normal cooling starts at 1.5V Vcore.

You'll run into thermal issues way before that though, unless you have delidded. At 1.30-1.35V where you'll probably max out (which cooler?) I wouldn't worry too much about longevity.

Clock rate doesn't kill CPUs, Voltage does. Don't forget that Haswell drops the voltage in idle or whenever it's not at full speed. The CPUs are supposed to last 10 years at stock voltage so running at slightly higher voltage a fraction of their life shouldn't have much of an impact. Plus you probably won't keep that CPU for much longer than 5 years anyway.