Does PCI Express 3.0 help with higher resolutions?

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NetTechie

Limp Gawd
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Jan 10, 2014
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I run my games on a 30 inch monitor at 2560x1600 resolution, and I notice that there are occasional halts in the fps, where it stops for a moment, especially in fast moving parts of games. I'm currently using PCI Express 2 on an AMD system... would having PCI Express 3 make a difference at these higher resolutions? I checked a review comparing the two slot technologies, and both results were almost identical. However, momentary glitches in fps might not have shown up with just pure FPS comparisons. Any thoughts?

To switch to pci express 3 I'd have to switch to intel obviously.
 
The only difference is memory bandwidth, and the difference isn't much between PCI-E 2 and 3 with modern GPUs. What graphics card are you using? The PCI slot shouldn't cause any glitches relating the FPS, it may cause textures to stream slower, but it shouldn't normally cause skips.
 
Yeah I was looking at that before I posted... but maybe the glitches are less than a second. Since FPS are Frames Per Second, glitchyness wouldn't show on a second to second comparison. I can say the glitches are not a full second, for sure, it's more like glitch glitch glitch, then smooth, glitch glitch glitch again. Battlefield 4 is the worst for these glitches.
 
I cannot find any graphs are count every frame. What games are you seeing this in? Does anyone here wants to run some benchmarks by switching PCI-E 3.0 to 2.0 in the bios? :p

I wouldn't expect PCI-E to be the culprit.
 
Biggest problems are in Battlefield 4, it's doing this a lot. Very annoying.
 
The 7990 and 690 are the only cards that really get any boost from PCI-e 3 and even then its small.
 
Must be I need a better graphics card for these resolutions... with the high prices on AMD cards on ebay, maybe I could sell it and get a GTX 780. Or maybe a crossfire/SLI setup, I have an Corsair HX850 power supply so I think it could handle dual graphics cards ok.
 
PcZac said:
I cannot find any graphs are count every frame. What games are you seeing this in? Does anyone here wants to run some benchmarks by switching PCI-E 3.0 to 2.0 in the bios? :p
Click to expand...

If someone had a 2560x1600 capable monitor, with Battlefield 4, a test for glitchyness would be greatly appreciated... I might switch to PCI-E 3 rather than upgrade my video card, if it fixes it! I'm seeing the glitchyness in single player, especially in large outside areas.
 
If your concern is BF4 I'd think you should wait and try out Mantle and see if that does anything for you.

The issue could be your CPU as well (which Mantle, or even moving to Win 8 for DX11.1 would help with).

What other games are you trying out and what settings? Keep in mind 2560x1600 is quite demanding for a single GPU of that tier as well. Most people looking for an optimal experience at that resolution are running the higher end GPUs or multiGPU configs.
 
Good to know, I was considering adding a 7950 to crossfire with the 7970, wonder if that would improve performance with the high resolution settings.
 
While it is technically possible to crossfire a 7950 with a 7970 according to most accounts it isn't the best experience.

The issue is because the 7950 and 7970 also differ in stream processor and texture units (not just clock speed) so there performance would be very asymmetrical causing smoothness issues. This is something different than the other frame pacing/microstutter issue you may have heard about.

Also from a cost and availability perspective I'm not sure if you will even be able to find a 7950? The 7950/7970 have been discontinued for the 280x (which is architecturally similar to the 7970, no 7950 equivalent currently). Existing cards are in high demand for scrypt mining as the 7950 is considered the most efficient for pure mining so don't expect any deals (if you can find one) on the used market.

Actually PCIe performance variation (to address your concern) if it existed would be compounded with a multigpu setup if you only have a single x16 which is then split into x8/x8.

The resale value of your 7970 and the cost of buying a 7950 would be higher than getting a 290/290x (even with the current mark up as well) and for sure a GTX 780 in the current market. I believe you could even get a GTX 780ti for the same cost at present.

From what I hear though currently BF4 is better performing (also smoothness) for AMD cards even without Mantle. Which isn't surprising due to the close development and cross marketing links.

Unless you want to consider reselling and are afraid the market value may drop I'd just wait for proper Mantle support for your 7970 and see how it goes and whether it improves your situation.

You could also consider doing some monitoring and seeing if you maybe anything unusual happens with these performance drips (eg. clockspeed drops, gpu usage drops/spikes, cpu usage drops/spikes, etc.) Or even drop GPU demanding graphics settings and see if it still occurs (would indicate it is likely another issue, possibly CPU performance related for example).
 
What is your VRAM usage like? Does dropping the visual quality stop the glitching?
 
I ran 7970 and 7950 in Crossfire. Smooth as butter but takes a little tweaking especially if you have boost bios cards. I had to basically disable boost by cranking power usage to +20% all the time to stop the 7950 from throttling and causing stutter issues. Not sure why but even in low usage scenarios (vsync on) it still wanted to throttle with the power set at stock. Also the 7950 at about 1075/1500 matched the 7970 at 1000/1500. Later traded the 7970 for a 7950 to match and still had to do the power adjustment and was just as smooth.

To answer the original question pcie 3.0 only makes a difference when running 3 or more cards at super high resolution (5760x1080 or 4k). In that case pcie 2.0 has a massive hit to framerate in a lot of titles. Around half of what pcie 3.0 can do.

http://forums.evga.com/m/tm.aspx?m=1537816&p=
 
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NetTechie said:
Biggest problems are in Battlefield 4, it's doing this a lot. Very annoying.
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If you're on Windows 7 you'll want to unpark your CPU cores if you haven't done so already. I was having the same kind of performance problems in BF4 with otherwise great framerates on an Intel 4770k and GTX 780. Unparking the cores eliminated the problem for me. If this doesn't solve your problem, try turning down texture quality and/or AA a notch. This kind of hitching can also be typical of a VRAM usage issue.
 
At very high resolutions with multiple GPUs the answer can be yes, but it depends on how many PCI-E lanes your board has already, the games in question, the settings you are running, etc. It's kind of a complex answer. If you are running 16x/16x PCI-E 2.0 then no, if you are running 8x/8x PCI-E 2.0 then possibly.
 
OP- How much ram does your current graphic card have? Armenius makes a great point (and, agreed, I've seen what you describe when a game maxes out the card's ram).

Here's some testing I did a while back on the topic: http://www.overclockers.com/forums/showthread.php?t=718118 (I haven't tested bf4 yet nor at your rez nor updated the chart but you'll get the idea). If your current card has 2.5GB or less of memory, that's likely the cause of your stuttering/suffering.

Update- Just took a look for your card...it has 3GB from what I can tell.

Install MSI Afterburner and set it up to log your card's memory usage (plus whatever other elements you want to see like fps, temp, etc). You can set it to report every frame if you want (I tend to set it for every 5 frames but you may want a shorter interval). Once you're set, start BF4 and play it as you normally do...the longer, the more datapoints, the more you can see what's actually going on during gameplay. Exit BF4 and open the Afterburner log file (I usually import the file into excel as it's easier to manipulate). After deleting all the measurements that were before or after your BF4 run (you'll be able to tell which ones those are), sort by memory usage. If you see entries that are greater than or equal to ~ 2.9GB, you're swamping your memory bus (you should also be able to see where your fps drops dramatically...but generally only if you set the logging to every frame).
 
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