So I got 16GB (2X8) DDR3-2400 for my 2500k but OC went unstable

[psolord]

Hey guys.

I recently got two sticks of Teamgroup Vulcan DDR3-2400 with capability of 11-13-13-35 @1.65V. This is what the sticker on the RAM says, but CPUz reports



That's not really the problem though.

So at first I just set them at auto, set the CPU at stock, selected XMP profile for 2133 (does not give me a selection for 2400) and this is what my motherboard (Asrock P67 Extreme 6) decided to run them at.





So we have 10-12-12-31 @1.65V for 2133mhz, while the memory's max is 11-13-13-35 @1.65 for 2400mhz. Good so far?

The system is stable at this frequency but only when the cpu is at stock. If I try to overclock even at a mere 4Ghz, which is my normal speed for this cpu, the graphics driver starts crashing but only when in Crossfire mode (7950 crossfire).

I know that you may think that the problem is elsewhere, but after quite some testing I found it was the ram speed. I mean if I reduce it to 1866mhz with tighter timings, the system runs fine. No more driver crashes.

Sometimes, I do get occasional lockups. I mean the system just freezes. It is one hour Prime 95 stable, but after 5 minutes of Shadows of Mordor with Crossfire enabled, boom, the driver crashes.

Do you guys have any idea why is this happening?

Should I fiddle around with VTT? Actually I have tried up to 1.15 but it didn't help. Do I need to go higher due to the RAM being large? People around the net were saying that it didn't matter, even for four sticks 2133.

 

[Yuriman]

Try seeing how high you can run the RAM using 1.5v, the out of spec voltage might be causing problems.

If you can't get the RAM speed higher I wouldn't sweat it though, anything past 1866 is going to be nearly margin of error difference.

 

[BonzaiDuck]

Try seeing how high you can run the RAM using 1.5v, the out of spec voltage might be causing problems.

If you can't get the RAM speed higher I wouldn't sweat it though, anything past 1866 is going to be nearly margin of error difference.

+1, :thumbsup::thumbsup: and posi-lutely, abso-tively true. Anything past 1866 is not going to reap any great performance increases with the Sandy IMC.

I had two kits of DDR3-1600 Ripjaws "GBRL" G.SKILLs which overclocked will to 1866 and 10-10-10. Needlessly replaced them with a 2x8GB kit of 1866 9-9-9-24 Ripjaws Z. That's about it. I'll bet that I can get easily to 2133 and loosen the timings to 10-10-10, but it won't be much worth the trouble.

I don't mind tweaking the VCCIO just a bit to make them run with CMD=1, though. that's enough for me . . .

 

[psolord]

Hey guys. Thanks for your replies.

Unfortunately I myself misled any help I could get, by saying that you may think the problem was elsewhere, but I checked.

Well I did check but it seems that I did not check enough.

To cut the story short, the actual problem lay with my second 7950. Not that it was broken. There was just something stuck and when it was trying to render it gave driver errors.

I kept lowering OC settings until I reached stock for everything and low ram speed and the system kept being unstable.

So I pulled out my primary card and left the secondary inside. When the system was trying to render, it was freezing. I thought it was a bad card, but then I put in on the primary slot and it worked fine.

Then I put the primary card on the secondary slot, so to check the slot and it worked fine too. When I put everything back the way it was, everything was working fine.

I am now at 4.8Ghz, but I did take your advice and set the ram to 1866Mhz with timings 9-11-11-28 with 1.6V. My Grid Autosport result only dropped 1fps out of 110.

I even managed to complete my Shadow of Mordor benchmark session, which is the heaviest game regarding ram I ever played (reached 10GB memory usage).

SHADOW OF MORDOR 1920X1080 ULTRA RADEON Crossfire 7950 @1Ghz CORE i5-2500K

thanks

ps It was one hour linpack stable as well, with maximum memory usage, so I guess it will be ok for my benchmarks.

 

[Yuriman]

Strange, but glad everything worked out for you!