DDR 2 Memory running slow - timing issue?

Andy_H · 12 Jun 2010 at 18:35

I'm running 800Mhz DDR 2 memory on an Asus M2V motherboard, but it seems to have dropped to 667Mhz.

Before I updated the BIOS CPU-Z saw my memory at 400Mhz as it should. After the bios update it is now running at 333.33 according to CPU-Z. However, there are now a lot of options under the RAM settings in the BIOS, whereas there were no timing settings before.

I'm guessing either somethings wrong in the BIOS settings or in the latest update they've changed something making this RAM incompatible (which seems less likely)

CPU-Z now:

And the BIOS settings at the moment:

Any help would be greatly appreciated

Thanks, Andy

johnerz · 12 Jun 2010 at 22:20

You will now have to enter the correct settings yourself
Change the memlock mode to manual and I think you can changethe settings in there

Andy_H · 13 Jun 2010 at 10:54

I've set the memory mode to manual now and tried entering both the 400Mhz timings at 1.8v (5 5 18 23) and the 4 4 4 12 24 timings at 1.95volts (the highest my board would go to)

Its still showing up in CPUZ as 366.6Mhz. When i was overclocking the chip last night from 4200 to 4600 the RAM frequency in CPUZ increased to around 380Mhz, is this because the frequency read in CPUZ is dependant on the FSB?

Phatzy · 13 Jun 2010 at 12:51

have you enabled EPP in the bios? and also is the second stick of ram the same as the OCZ?

Andy_H · 13 Jun 2010 at 13:51

Both sticks are the same (http://www.crucial.com/uk/store/partspecs.aspx?IMODULE=BL2KIT25664AA80A). I can't find an option in the BIOS for EPP, i'm assuming because its an old board it doesn't support it.

mame · 14 Jun 2010 at 10:22

The motherboard is resorting to the fail-safe RAM settings because everything is in auto. Set the memory voltage (VDIMM) to whatever the RAM manufacturer rates the RAM as then set the rated timings. Timings are nothing to do with RAM speed apart from if you get to the point as using slacker timings to acheive a higher RAM speed.

The reason it's running just below its rated 400mhz is probably because the memory divider is on auto. The next divider up might put the RAM @ 408mhz (a guess) so the motherboard will look at that and decide against it because it's faster than standard and decide to use the next divider down giving you what you have now. Yes, upping your FSB will increase your RAM speed a bit at a time. If you left all RAM settings on auto and continued to up the FSB, once you past the 400mhz RAM barrier, the motherboard would lower the divider again to compensate.

If you were to manually set the RAM divider but leave the timings on auto you might get some mad timings being used as it tries to compensate for the fact that time RAM is running 'too fast', even though it's only a few MHz. you might see (a guess) 415mhz 7 -9-9-42 which obviously you don't want. Even though that situation is a bit daft because it's very unlikely that the RAM won't run slightly over its rated speed, there are situations where running RAM quite a bit faster than standard can be achieved by offsetting this by using slacker timings.