Enabling PCI-E Gen 3 on R4F

[thebski]

Hey all,

I got a 3930K and R4F about a week ago, and when I first installed everything I installed the PCI-E Gen 3 patch for the GTX 600 series cards. After I did that GPU-Z was showing PCI-E x16 3.0. I just looked today for kicks and it is now showing PCI-E 2.0 again.

I tried redoing the patch but it still shows 2.0. I looked in the bios and Gen 3 is enabled. I have no idea what could have changed it. Anyone else seen this or had trouble getting this patch to work?

[HiVizMan]

Me I am not even bothering to run the batch. What real world difference am I going to see in my games?

Have you updated your nVid drivers? Have you made any changes to your power plan, AV or system cleaning software.

Short answer no idea why the patch does not work 🙂

[thebski]

Yea I'm thinking it is something driver related as I've tried a couple different drivers. I might try driver sweeper or something and a fresh install of the drivers.

You won't see any real world difference with one or two cards, but quite honestly PCI-E 2.0 is why I upgraded from Z68 to X79. I had 3-way 670's and I was seeing very erratic GPU usages and most of the time usages were under 70%. I was not happy as 3 GPU"s running at 66% equals one completely wasted $400 GPU. And my results now with SLI show basically just that. My performance is not that much less at all than it was with 3-way SLI.

After reading around on the internet and finding Callsignvega's PCI-E 2.0 vs. PCI-E 3.0 thread found here I decided that that's exactly what my problem was with my Maximus IV Extreme. My symptoms acted exactly like a CPU bottleneck just as Vega describes in his thread even though my CPU usage would drop from 45% to 22% when the GPU usages would go way down.

The interesting part was that while running PCI-E 2.0, the GPU utilization dropped way down as would be typically seen if you are "CPU" limited.

GPU utilization dropped down into the ~50% range due to PCI-E 2.0 choking them to death. As soon as I enabled PCI-E 3.0, the GPU utilization skyrocketed to 95+% on all cores.

That is somewhere in Vega's OP in that thread and pretty much describes exactly what I was experiencing. While his usages were in the 50's due to 4-way SLI I mostly saw usages in the 60's and 70's with 3-way. Still very frustrating to look up and see 66% or less usage across the board and know that my 3rd card is literally doing nothing for me.

So short answer no you won't see real world difference with one or two cards and single screen resolutions, but once you start pushing 3 and 4 cards and triple monitor resolutions you will be bottle necked by PCI-E 2.0. It's not necessarily a huge deal for me right now as I had to trade away the third card for the processor, but if I ever went 3-way again I would definitely want PCI-E 3.0 to be running properly.

[HiVizMan]

Totally agree with you thebski

[thebski]

Well unfortunately a clean install of the 304.79 beta drivers after running driver sweeper did not do anything for me. The quirkiness I have been experiencing with this machine the past couple months has just been maddening and I suppose this is just another item on a laundry list of things. It seems I do 3x more troubleshooting than gaming these days. Pretty frustrating for investing so much money in all the highest end hardware:confused:

[HiVizMan]

I would sympathise with you if I did not know you better, and know how much you like to tinker and find stuff out. I am sure that within a couple of days you will have found some work around or tried something else. 😄

Let me share one shocking thing with you. I find that two cards - regardless of if they are from the red or green team is pretty much the max you need for any situation. Three and four is just a steep diminishing return of investment. I see this all the time when I bench Tri or Quad VGA - and in some instances dual card is even more efficient due to the excessive bandwidth budget.

[thebski]

Yea I found the same with 3-way and that's why I was so willing to trade my third for a new 6 core. Not only was it not gaining me anything due to PCIe bottle neck, I was still running stupidly high frames at 5760x1080. It will be a while before I potentially buy a 3rd again.

And you are correct! I figured it out and boy oh boy was it simple and a stupid error on my part (almost always is:p). You have to run the patch as an administrator for it to do anything. I finally ran it as admin and what do you know it showed PCIe 3.0 after a quick restart! Simplest patch ever to run as long as you do it as an admin!

Thanks again for chiming in HiViz!

One quick question. I just want to pick your brain a little bit. What do you think about the 2GB vs. 4GB for the 600 series debate? I personally tried the 2GB 670 FTW's from EVGA and found that I was happy with the settings I could run even if it means no MSAA in games like BF3. Have you had much experience with 4GB cards? Do you think there are real advantages to having 4GB if you have played with them?

[HiVizMan]

It is often the most obvious that we overlook, mainly because we are always looking for complex reasons. And it is the simple that catches us out. What I am pleased about is that I was right in my valuation of your skills as a finder of solutions.

4GB v 2GB Hmm not as easy a question as one might think. From a benchmark perspective, there is nearly no tangible gain in performance over the 2GB cards. From a gaming perspective, I think that there are maybe two games that will seriously benefit from the cards with more memory. Is that extra bit of eye candy worth the additional $100 for essentially the same card? Em no. And yeah that is taking the huge resolutions that we play these days into account. If you can afford it why even ask the question. 🙂

Don't see that many Ferrari GT buyers asking about fuel economy.

[thebski]

Haha very true story HiViz. I originally wanted 4GB cards but I got tired of waiting and once I played with 2GB I knew it was plenty good enough for me. The cost was going to be a big increase as I would have had to buy 4GB 680's + water blocks which would have probably been $1500 as opposed to $1000 for these 670 FTW's + water blocks. It just wasn't worth the extra $500 to me. By the time 4GB was truly necessary then I'd have the upgrade itch for 700's or beyond anyways.

I'm pretty satisfied with my system where it is at now. I'm somewhat of a perfectionist in terms of balance and getting the absolute most out of everything, but I think this X79 platform with these two 670's is just a real screamer. X79 is going to be a good platform for quite a while I have a feeling. Max cpu usage I see in BF3 online is a measly 30%. Crazy fast!

[HiVizMan]

And what is your CPU frequency when you only get 30% usage? I found my sweet spot was 4.2 for single VGA and 4.4 for dual VGA.