PCIe 3 motherboard

[RAA]

Hi, I got a Sabertooth X79 motherboard and have 3x770GTX in it. I can get PCIe 3 working but after a while the system glitches, framerates drop and it grinds to a halt. Sometimes it goes black and on reboot it says the overclock failed. I'm not 100% sure it's PCIe 3 yet but these symptoms sound like it is PCIe 3 judging by what I've read.

Am really quite annoyed about it as the mobo box and graphics cards all say PCIe 3. My CPU is i7 4820K Ivy E at 4.7Ghz prime stable. So I was wondering, is there a motherboard that is 100% stable with PCIe 3 or does it depend on the CPU, some work some don't?

I want to get PCIe 3 working because on triple screen resolutions it adds about 25% performance. Appreciate any help thanks.

 

[Lvcoyote]

Try setting the CPU to stock speeds and see what happens, it's possible the error message you're seeing is telling the truth....LOL

 

[RAA]

But it runs for 24 hours in prime95, none of the 8 cores fail, 0 errors. I might try that though, does anyone know if these PCIe 3 errors are sensitive to overclocking? I'm 99% sure it's PCIe 3, it usually stutters once after running perfectly for 30 minutes or so, then it just goes downhill after that with more and more suttering. Sometimes it goes to a black screen, sometimes I can exit before it goes to a black screen.

Is there no system that can run PCIe 3 100% without a hitch currently? Or does it depend on CPU, some work some don't, any info on what causes the error exactly?

 

[Lvcoyote]

X79 platform was released before PCI-E 3.0 came out. That being said, the CPU you're using is said to support it, but a lot of people have had issues trying to get it to work properly on that X79 platform. The Z87 stuff supports it completely with the right CPU, say a 4770K for instance.

I would still try without overclocking the CPU for a test, and also make sure you have the latest BIOS for the motherboard.

 

[RAA]

Done some searching and I've not a read about a specific fix but it does seem to be a CPU by CPU specific problem and some instances of replacing the CPU fixes the problem. So I took out 8gb RAM, going from 16gb quad channel to 8gb dual channel. Perhaps quad channel is stressing the CPU too much. Funny thing is that when I took out 8gb it would not boot, the red light for RAM issue was on. Swapped those two sticks for the other two and it booted! Even stranger is that it boots in quad channel with those non booting sticks in those slots and is prime95 stable.

It just ran iRacing for about two hours without a problem using PCIe 3 however I wonder if realtime gameplay instead of a replay will break it again. FYI at 5760x1080 framerate with a full grid at the start is 190 without PCIe 3, 280 with it.

 

[ATMINSIDE]

Prime95 is a good test for general stability. It is not an end-all be-all test.

Sounds like you have a (or a pair) of dying RAM, have you run Memtest86+ with all four sticks in?

 

[RAA]

No I haven't, only prime95 and games. The funny sticks are only a few months old and I know that Corsair sticks with Sabertooth X79 are fickle, some work some don't. For example it won't even boot with one stick, in some slots, doesn't matter which stick I use. I have read that this motherboard works fine with Kingston HyperX. It's not so much a stability issue, more a booting and XMP profile issue however it's a bit suspect how one pair boots and the other doesn't, will try Metest86+ thanks.

 

[ATMINSIDE]

G.SKILL is typically very good in regards to compatibility with AMD.

Let Memtest86+ run for a few passes.

 

[RAA]

Well it grinded to a halt again, disabled PCIe 3 and it hasn't grinded to a halt yet and I doubt it will. Not sure what to do, don't think overclocks affect the error, from reading bits and bobs it sounds like some CPU's error and some don't and judging by how few complaints I've been able to find, the error may be rare. So I think I might try a 4930K, if it works I will RMA 4830, if not I'll sell them both and upgrade to Haswell. Are you sure Haswell has absolutely zero issues with PCIe 3?

 

[RAA]

Well it's done it again with PCIe 2 enabled in bios. I can also check speeds with a little CMD utility for actually bandwidth speeds and they were PCIe 2, GPUZ also says PCIe 2. I did not revert the patch, could it be that the cards are running at PCIe 3 while the system is PCIe 2, anyhow will check that.

Now suspect that this issue is caused by displaylink driver for USB display or maybe it's just my mobo not liking the Corsair RAM.

 

[Lvcoyote]

I would still try without overclocking the CPU for a test, and also make sure you have the latest BIOS for the motherboard.

 

[RAA]

Well well, I lowered OC to 4.4ghz with 1.4V, it has ran an hour long replay almost three times and done 2 60 minute races without a hitch, that's with PCIe 3 enabled and 16gb quad channel.

Many thanks for tip. Previously it would usually error within 90 minutes and today it's done 360 minutes, hopefully it's safe to say it's now stable, pleased I don't have to buy anything to fix it and glad I've not been done over by PCIe 3 error as that's the main reason I upgraded.

 

[Lvcoyote]

Glad it seems to be working, I had a hunch the OC was holding it back.

 

[Ajay57]

Now you know its your OC you can play around with that to find the best setting. Also would up date your SIG please, as i have to keep going back to your first post to remember what your using that end lol!!

Hopefully it will run now without anymore problems, good call LV!!

EDIT: Try unlocking your CORES that will also help you in Gaming.

AJ.