I have the same mouse/mousepad combo and the EC1 seems to have a hard time with handling fast movement on the 9hd on lower sens's. Try increasing the DPI, if you haven't done so already, that seemed to help mine at least

almost every single mouse has a maximum speed it can keep tracking on - are you maybe going beyond this speed? (when set to 450 or 1150, the max tracking is a lot lower than when set to 2300).

since you're using 450, i fear it might just be the maximum tracking speed getting the best of you. try 2300 cpi (and lower your in-game sense accordingly) and just jump around a map for a minute, to see if you still have the same issue then?

also, why 5/11 windows pointer speed? ;p 5/11 will probably not do harm, but we all know 6/11 is the only truly flawless setting

edit: well, i guess wally beat me to it

Changed dpi to 2300 and lowered sens in-game. Same problem :(

Probably gonna have to get a cloth pad

I just made the change from 400 dpi on a Logitech G500. So lowering Windows speed by 1 made it almost the same to what I was used to, it seems to have no effect in-game

Used Logitech for well over 10 years (mx500 > mx510 > mx518 > g400 > g400s). Between the g400 and g400s I tried an EC1 and an FK and had the exact same issue, someone mentioned that ZOWIE mice didn't like multi-coloured mats (have a Talent) and I wasn't prepared to use any other mat so I went back to Logitech and ordered a g400s. Think the 9HD is also multi-coloured so you could try it on a single coloured mat!
My advice would be sack ZOWIE off and stick with what you're used to, especially if you're a low sens internet boy. Any mouse that costs as much as they do shouldn't be kicking up problems.

I just left my G500s because the cable problem kept occurring. So I thought I'd check out the rave of Zowie

:D Don't get me started. That's the reason for all my mouse changes! Think I went through 4 mx518's and 3 g400's which were all replacements from Logitech before being given a g400s by them. Sometimes they've lasted a couple of years, sometimes a couple of months. So fucking annoying, especially after buying a mouse bungee and it making fuck all difference.
My g400s just packed in at the end of August from general use (very rarely have time to play games nowadays) and I was unable to get a replacement because Logitech have changed their policy and now only offer replacements if the original mouse that went faulty was purchased under 3 years ago. Shafted me because my latest mouse was a replacement of a replacement of a replacement of a replacement etc. I've been told the cord problem has been completely eradicated with the latest range of mice so I've been eyeing up a g402. Reckon I'll wait till I can commit more time to gaming than a couple of hours per month before I throw money at a mouse though.

If you're intending to stick with the EC1 then there's really no other option but to get yourself a single coloured mat, but I do know of people who've reported the same problem using one of these also. I don't see the point in throwing yourself off kilter and increasing your sensitivity/DPI just so a mouse that is nearly twice as expensive as most Logitechs can cope.

EDIT: Just been speaking to a friend about your problem and he swears the latest version of the FK, FK1 has addressed the problem. If you are truly fucked off with Logitech you should maybe give it a whirl.

I've never looked at the G402, it actually looks very good, it looks impossible for that cable to be broken. It's very similar to the G500, but has a fixed cable.

I've decided to get another G500s and treat it like a baby. I was very happy with the EC1 until I came across this problem, I've heard they're doing a reboot of it so they might fix it. Spent £150 in the past week on mice, just guess I've had bad luck! I just want to not have to worry about it, I have to restart my PC if my G500 disconnects because it totally locks up and I can't do anything to reset because it locks up my keyboard too. So annoying in scrims.

I have a Zowie EC1 EVO on a Steelseries QCK Heavy pad(cloth). Same issue, seems like the sensor just can't handle fast flicks. It's kind of annoying, I bought the mouse as an upgrade to replace my Black Edition DA, seems like it was more of a downgrade, although it's more comfortable but still meh...

both my EC1 eVo and FK were perfect on my PureTrak Talent

Had the same issue with my ec1 evo. Zowie said they would RMA it, however buying a different mouse was cheaper than the shipping.

Please tell me you do not have smooth mouse enabled in your in game options.

It happens on my desktop too as stated in the op so it's nothing to do with my game settings

k well its because of the custom lens for low lod which can make it unusably low.
regardless whether you're lifting the mouse it is the reason.

you can mod the lens and your problem will be fixed.

without writing an essay just open the mouse and take out the lens and you will see its molded in two parts. 1 part is the custom piece zowie added and pry it off with a small screw driver and reassemble the mouse. last step is optional but you can deflect the extra light by taping a strip of aluminum foil on the bottom of the mouse behind the lens opening and pushing it down into the opening.
disclaimer: I've only done it on an orignal fk but it had the same problem and this mod made it flawless

also, while its not related to this problem, pls no 5/11 windows cmon dude

I used 1150 dpi .89 ingame with 5/11 windows before, I noticed no issues with my ec1 and have rocketjumped for quite some time, make sure you are using the mouse fix for custom windows sensitivities or else you will get skipping on movement and everything will suck. With the fix using custom mouse settings are fine, I am also using a steelseries pad and have not had any problems. Use a sensitivity calculator if you dont want to use a mouse fix to replicate your ingame sensitivity to 6/11 and see if that would fix any problems.

ooh i thought i was having this same problem but there was just a hair in my sensor

that was a close one

clean your mouse people

Back in January of this year, Zowie came out to say that they recalled some previous mice. It's possible it's related to your problem. A link can be found here.

Doesn't say anything about sensor issues.

My EC1 eVo did the same thing. I bought an EC2-A and it works flawlessly.