Well I guess now you know why buying headphones blind isn't a good idea.

I know it's not helping, but why did you get closed headphones if you wanted open headphones?

#506
Any GPU is compatible with any motherboard, you don't need to worry about that.

However you shouldn't upgrade just to upgrade.
Do you want/need more fps? No -> don't upgrade, save yourself that money.
If yes, which games and how many fps? Then if it's your GPU that's limiting the fps, pick one that'll get you enough fps, don't spend all the money you have, just because you can.

Even though my eye started twitching a little when I looked at the PSU I don't expect that system to fail anytime soon.

#507
280 should simply be much cheaper. 285 or 280X are also worth a thought, if there's one on sale.

Check SMART.

Would've gone for H97 for the usual reasons, but what's the point of going full ATX if you don't even get 2*x8. No one needs 4 x1 slots. Doesn't hurt that the PSU would allow for SLI/Xfire aswell.

If you want to save 10$ go mATX.
PCPartPicker part list / Price breakdown by merchant

CPU: Intel Xeon E3-1231 V3 3.4GHz Quad-Core Processor ($241.95 @ SuperBiiz)
Motherboard: ASRock H97M Anniversary Micro ATX LGA1150 Motherboard ($64.99 @ SuperBiiz)
Video Card: PowerColor Radeon R9 280 3GB TurboDuo Video Card ($149.99 @ Newegg)
Total: $456.93
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-05-29 12:07 EDT-0400

Another option would be the Z87-Pro for features.

#1
The answer to your question would be yes.

#501
In that case my recommendation is building it yourself, if possible.

No idea regarding windows, sorry.

#502
That would've been my point, for 50$ you could go fanless and at least µATX, ECC RAM if you wanted to and so on. Phenom is just the complete opposite of what you'd want for a media server and no undervolting is going to change that.

The PSU should definitely be ok then, I guess you see why I don't trust the other 3 versions.

This is as low as I'd go:
PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4590 3.3GHz Quad-Core Processor ($189.95 @ SuperBiiz)
Motherboard: ASRock B85 Anniversary ATX LGA1150 Motherboard ($59.98 @ Newegg)
Video Card: Sapphire Radeon R9 270X 2GB Dual-X Video Card ($124.99 @ Newegg)
Total: $374.92
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-05-29 06:03 EDT-0400

It should get you enough fps, but just barely. So worst case TF2 spazzing out and you might get a CPU bound drop, 10v10 CS:GO worst case and you might get a GPU bound drop. With quite a bit of buffer (you never know when the next "performance" update hits) it would look like this:
PCPartPicker part list / Price breakdown by merchant

CPU: Intel Xeon E3-1231 V3 3.4GHz Quad-Core Processor ($241.95 @ SuperBiiz)
Motherboard: Asus Z87-A ATX LGA1150 Motherboard ($74.98 @ NCIX US)
Video Card: PowerColor Radeon R9 280 3GB TurboDuo Video Card ($149.99 @ Newegg)
Total: $466.92
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-05-29 06:06 EDT-0400

How exactly are you going to use the media server?
And where do you want to put it?
Because small and efficient isn't going to happen with an ATX mobo, a 125W CPU and a 125W GPU. Sure you can undervolt and underclock them, but even with a PSU with 100% efficiency you're still not going to beat a 10-20W integrated board and any PSU. Also no point in getting slower RAM, it'd be too hard to find.

You'll also need to be a bit more specific about the performance. With no budget it's the only thing to go on and barely 240fps on minimum settings with an fps config in 6s has a lot lower requirements than 240+ fps at all times on max settings in a full pub server.

Model number for the PSU would be helpful. Because there's 4 versions.
CMPSU-750TX, 80Plus, CWT, barely passes ATX spec
CMPSU-750TX-C, 80Plus Bronze, CWT aswell
CMPSU-750TXv2, 80Plus Bronze, Seasonic and actually decent
TX750, 80Plus Bronze, CPT, complete wildcard, no reviews, platform is unkown, but I highly doubt that it's amazing.

It's not too bad, at least not one of those retarded 4770K + H81 + GT740 pre-builts.
It still suffers three of the usual pre-built problems:
No SSD.
Shitty case.
Shitty PSU.

I have no idea about the prices in Hong Kong though, could you link me an online shop?
Going by US prices it's ok-ish. http://pcpartpicker.com/p/VVTpLk
But it could be done better, especially if you build it yourself (no labor cost). http://pcpartpicker.com/p/k3XJD3

I have been summoned.

low GPU usage: normal, you were bottlenecked by your CPU before and now with a more powerful GPU it's even worse.
lower fps than before: I'm not sure if I should believe you, but you could try the 340.52 driver anyway.

EDIT: fixed typo

So calling out stupid decisions is ad hominem now?
And if I don't care about your feelings because I'm not paid to do so is dissonance?
Oh boy, I suggest you leave the internet now before you get even more offended.

1. Won't cut it for TF2.
2./3. Either you bought the monitor without knowing wether or not it would work or you bought it after I told you it won't work. It doesn't make sense. You just wasted 200$.

Either you completely ignored my advice and bought the monitor anyway or you're really salty that after you bought the monitor you found out it won't worked like you planned.

That's nice. Actually you didn't ask for anything in #396.
But I don't care. I'm not Tech Support. So if I see stupid shit, I'll call it stupid shit, no sugarcoating.

How do you plan on getting enough fps with that craptop to justify a 144Hz monitor?

http://i.imgur.com/pret5yL.jpg
Read the list under "Preset Graphic Modes / Supported Resolutions"
And quoting the description

1. You are not getting enough fps to justify a 144Hz monitor.
2. The monitor doesn't support high refresh rates at low resolutions.
3. The HDMI port doesn't support high refresh rates.

To make this abundantly clear I'll translate it:
1. This setup makes no sense
2. This setup will probably not even work.
3. This setup will definitely not work.

No offense intended, I'm just baffled how you could think this was a good idea.
I mean from my perspective this just happened:
You: "Can I run 144Hz through HDMI?"
Me: "144Hz probably not, maybe 120Hz if you're really lucky."
You: "I'm playing on a craptop that won't get good fps."
You: "144Hz won't work on that craptop."
You: "But I can't afford a new pc yet."
You: "So I just bought a 200$ 144Hz monitor anyway because 144Hz is best and 200$ is so cheap for a 144Hz monitor."
You: "This will totally improve my gaming experience and accelerate saving up for a new pc."
Me: head -> table

For GTA5 and BF a better GPU would actually make sense.
Bigger SSD aswell because why not.
Better (because I love good PSUs) and fully modular PSU (because it makes building so much easier).
Since you got a Mid Tower and a good PSU now anyway I changed the motherboard so you could in theory go SLI in the future. It's unlikely but it's a good mobo and 10$ isn't that much.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Xeon E3-1231 V3 3.4GHz Quad-Core Processor ($231.95 @ SuperBiiz)
Motherboard: Asus Z87-A ATX LGA1150 Motherboard ($74.99 @ NCIX US)
Memory: Mushkin Stealth 8GB (2 x 4GB) DDR3-1600 Memory ($47.99 @ Newegg)
Storage: Crucial BX100 250GB 2.5" Solid State Drive ($87.30 @ SuperBiiz)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($44.10 @ SuperBiiz)
Video Card: PowerColor Radeon R9 290 4GB PCS+ Video Card ($229.99 @ Newegg)
Case: NZXT Source 210 Elite (Black) ATX Mid Tower Case (Purchased For $0.00)
Power Supply: EVGA SuperNOVA GS 650W 80+ Gold Certified Fully-Modular ATX Power Supply ($64.99 @ NCIX US)
Total: $781.31
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-05-24 17:38 EDT-0400

#491
To only get 100+ fps at that budget something would have to go terribly wrong, 200+ fps is a more realistic goal.

Reusing any SSDs/HDDs or PSU?
How much storage space do you need?
Overclocking yes/no?
I'm having a hard time filling that budget.

Basic build for TF2/CS:GO would look like this:
PCPartPicker part list / Price breakdown by merchant

CPU: Intel Xeon E3-1231 V3 3.4GHz Quad-Core Processor ($231.95 @ SuperBiiz)
Motherboard: ASRock H97M Anniversary Micro ATX LGA1150 Motherboard ($62.10 @ SuperBiiz)
Memory: Mushkin Stealth 8GB (2 x 4GB) DDR3-1600 Memory ($47.99 @ Newegg)
Storage: Crucial BX100 120GB 2.5" Solid State Drive ($59.40 @ SuperBiiz)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($44.10 @ SuperBiiz)
Video Card: XFX Radeon R9 280 3GB Black Edition Double Dissipation Video Card ($149.99 @ Newegg)
Case: NZXT Source 210 Elite (Black) ATX Mid Tower Case (Purchased For $0.00)
Power Supply: Corsair Builder 500W 80+ Bronze Certified ATX Power Supply ($29.99 @ Newegg)
Total: $625.52
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-05-24 11:24 EDT-0400

Unless you're playing on really high settings I can't justify a better GPU.
I mean I could throw in an 4790K and the usual overclocking shenanigans.
http://pcpartpicker.com/p/VFBbzy

Or even SLI capability
http://pcpartpicker.com/p/yj3bzy

It just doesn't make a whole lot of sense.