Downclocking 1600 DDR3 RAM

Hi all,

I have an issue carried over from the General Hardware thread which I thought might get better views here.

I have Gigabyte GA-970A-UD3P motherboard and an AMD Athlon II X2 260 cpu. When I use my 2x2GB Mushkin DDR3 1333 RAM everything works fine, but when I try to replace this with 2x4GB Crucial DDR3 1600 RAM the system becomes very unstable. I can boot to Windows 7 64 Bit with no problem, but when I try to actually do anything (e.g web surf or gaming) the system either refreezes or reboots.

I have run Memtest through all 8 passes (which took around 10 hours IIRC) and it reported no problems with the RAM. I also tried some Patriot Viper RAM, also 1600, from my other rig and encountered the same issues. It definitely seems to be the combination of motherboard / CPU / RAM that is causing the issues.

It's been pointed out to me that my CPU doesn't recognise RAM above 1333, which may be my issue (although it worked fine on my previous Asus M4A77T/USB3 board). According to Crucial themselves they have advised not to downclock the RAM, although I don't know if that's just the official line to protect themselves. I could RMA and get 1333 RAM, but if I can I'd like to keep the 1600 as I plan to upgrade the CPU in the future to an FX-6300, which shouldn't have the same limitations.

The Crucial RAM has 11-11-11-28 timings and runs at 1.5V. What I would like to know is whether it's advisable to downclock it and, if so, whether I need to mess about with the timings, too. When I set to Auto I get no joy. If it helps the RAM part number is CT51264BA160B.

Any help greatly appreciated

it should down clock just fine, just set the speed to 1333 and go.
I went through some ram testing just a bit ago and ran 2400 ram all the way down to 1066.

thanks for the advice. I set the speed for 1333 as suggested. As a warning to anyone using the Gigabyte GA-970A-UD3P motherboard it then took it upon itself to reset the timings to 9-9-9-24 (the defaults are 11-11-11-28) and the system crashed again. I went back into the BIOS and manually adjusted the timings back to the defaults and the system has been running for the last 15 minutes or so, which is longer with this RAM than ever before. Fingers crossed the problem is solved!

I downloaded Prime95 and ran a stress test, which reported everything as stable. I just used the defaults but it seemed really quick and only took a minute or so. Is this normal?

Which stress test did you run? NONE of them take a minute. If you are testing memory with prime95 you need to run the BLEND test.
1333 @ cl 11 is TERRIBLE though.

Post up cpuz screenshots of the SPD tab please...

it's a new warranty replacement of existing RAM I already had. CL11 was the default speed.



oh, and my bad on Prime95. There's no hint it's actually running anything, just a text box, so I thought it was done. Still going with no faults as yet

You are running the torture test, blend, right?

Also, those should run at 9-9-9-xx. Look at the 685 speed (685×2=1370 or a bit faster than 1333). As I said, cl 11 and 1333 is SLOW.

Yes, I'm running the Blend test. Going strong at the moment.

I know what you mean about the timings. But the trouble is running 11-11-11-28 at 1333 is the only time I've managed to get any stability with this RAM whatsoever. It crashed when running 11-11-11-28 @ 1600 (the default specs). It crashed when running 9-9-9-24 @1333. But running 11-11-11-28 @ 1333 seems to be fine so far. Don't know why this should be

It shouldnt is the point.

I don't quite understand it myself but it seems to be the only way I can get it to work. Prime95 has been running for a couple of hours now and no problems reported

crucial has issues with amd, I have some crucial ram, to run it on any of my amd stuff is work, with my intel stuff it's plug and play.......go figure.
so i simply don't by kingston or crucial ram any more because i had both amd and intel rigs, now just amd at home.

The odd thing though is that my Crucial RAM worked fine with my previous Asus motherboard and worked immediately. It's only since I "upgraded" to the Gigabyte board that I encountered any issues, so on the face of it it looks like Gigabyte are a little more sensitive than others, too.

Manually stopped the Torture Test after 19 hours and 39 minutes. No errors or warnings reported, so system looking stable with this configuration, finally. Can now move on with the planned upgrades at last