Poor Computer performance

Afternoon guys,

I finally got my wattage cottage fully together complete with a PC based around a chinese X79 motherboard.

I have a 6C/12T Xeon E5-2640 0 @ 2.50GHz, RX470 and 12gb of really slow ECC ram (1033mhz)

I was wondering if any one could help me as I just get shockingly bad Zwift performance. I have monitored CPU & GPU usage with HW info and it seems my CPU is only being utilised to 10% and GPU usage/frequency is constantly up and down, but average 18% overall usage.

Now I am quite a computer geek, but I am new to Zwifts quirks, am i missing something simple here. I was thinking about hardware bottlenecks but the overall low utilisation of CPU and GPU doesnt seem the case? maybe the slow RAM is holding me back?

Also i would like to add changing resolutions literally makes no difference to the performance i have seen

any help would be appreciated.

I also have a HW info log file if anyone is interested.

Very weak CPU is holding back your GPU (which will never be great in Zwift due to AMD’s rubbish OpenGL driver), and your RAM isn’t even recognised by the game, meaning you’ll be getting low quality textures automatically.


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Hi dave, thanks for the heads up regarding RAM. I’ll have a rummage around in the spare parts box. Also will look into getting something with a bit more horsepower cpu wise.

That RAM isn’t the quickest I admit but won’t be choking performance to the extent you’re getting.

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Please can you tell me how you got the screenshot of this information. Thanks

It’s from putting a Zwift log file into zwiftalizer.com

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That’d what I thought Stuart. I can run Heaven Benchmark 1080p medium at 80fps. I’m pretty sure that is more taxing than Zwift.

I’m a computer guy but I don’t know the specs on RAM and GPU’s to comment, seems like great input from those that do. One thing I wanted to mention however is the ups and downs of frame rate are fairly common (at least on my laptop that cycles between 30 and 45 fps using the Intel intrinsic GPU) and appears to be dependent on the number of other riders the system needs to compute and display at the time. If you are riding a very popular route with many other Zwifters, or a group ride, your frame rate will be lower. If you are less busy road with less real time content to render, it will be higher.

A nice hack you can do to observe your frame rate in real time is to add the line “set gShowFPS=1” to your graphics configuration file at: C:\Program Files (x86)\Zwift\data\configs\high.txt You’ll then see the fps in the upper left corner of the screen in game. See these couple articles in ZwiftInsider show FPS and this one ZwiftInsider config file tweaks

I see you are running 1440 resolution, one suggestion would be to lower that to 1080 and see if you get better frame rate. The loss of a little resolution will be minimally noticeable, but the increased frame rate will be very noticeable and probably a welcome tradeoff.

Hi Joel thanks for your input. Thats one of the issues i have noticed however, i can cycle through low to ultra and its doesn’t impact the performance at all?

One thing i did notice, and have read about on a different forum post is the RAM stats not showing during zwift analyser logs. I have 16gb of hynix ECC ram. The amount shown in resource monitor is 16304mb, however, the amount shown in the motherboard bios is 16384mb. I wonder if this is throwing something off?

He’s already said that resolution makes no difference, and that’s because the GPU isn’t the problem. It’s the CPU holding it back. Lowering resolution doesn’t improve anything because the GPU isn’t at full load anyway.

RAM speed is virtually irrelevant in Zwift btw, the only real impact is the quality of textures when you’re below 8GB. None being detected gives the same result. I suspect it’s because it’s server RAM. OP should try updating his BIOS to see if that helps. But it won’t do anything for the frame rate.

Heaven benchmark isn’t more taxing than Zwift and results there aren’t reflective of much because it’s completely different. It allows your GPU to run to its maximum, by design. Zwift rarely does.

The problem is that your Xeon is on a server class socket, and it’s Sandy Bridge. So it’s not easy to get a meaningful upgrade, and it’s a pretty slow platform anyway.

Something like an E5-2643 should work on your board and is only a tenner on eBay. But it’s false economy really, when Haswell is also cheap and such a massive improvement. Unfortunately you’ll then run into the AMD thing anyway. Their Windows drivers for OpenGL (which Zwift runs on) are pants compared to those from Nvidia.

Hi Dave, having run a few more tests I’ve come to the same conclusion. Cpu thread 12 is constantly pegged at over 90% I guess zwift doesn’t do multi threading very well.

This pc I use for zwift was just a fun side project. I do have a ryzen/vega system I can use. I may see about getting a sandy bridge i7 and some ‘normal’ RAM. Dont really fancy shelling out for Haswell as that is also massively dated now. Thanks for the help everyone.

Haswell is by far and away the best value for money when it comes to Zwift, that’s why I mention it. An i7 on Sandy Bridge is significantly behind a Haswell i3. The game barely uses more than one thread, in fact a dual core Pentium G3258 smashes it with a nice overclock. A Haswell motherboard, CPU and RAM can be had for under £60. You’ve got to spend a small fortune on a CPU approaching 5GHz to significantly better it - and that’s only in group events where the frame rate tanks for pretty much everyone.

Likewise you only need 8GB of DDR3 RAM, and even that is only to avoid the crappy LQ textures. Performance holds up with as little as 2GB, I’ve benched it.

Obviously all this only applies to a dedicated Zwift rig.


Like this. :joy:

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Now you’ve spelt it out to me, I’m intrigued.

Dave is the best here, all Win users can be happy he helps.
Thanks, @Dave_ZPCMR !


Gahaha, just a dweeb. :wink:

As an experiment I got a e5 2643 as recommended for £10. See what the score is then. I will need some more ddr3 regardless, but you can get non ecc samsung stuff on ebay, £12 for 4gb 1600mhz.

Just also had a quick look at Haswell stuff on ebay and seems you can get some bargains.

Again Dave thanks for taking your time to help out.

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£7.95 delivered for 4GB DDR3 at CeX. :wink:

Legend. You’re the man !