Memory Question

[DarkAngel]

I just purchased Kingston (HyperX 4GB (2x2GB) DDR2 8500C5 1066MHz Dual Channel) and i have just noticed that my motherboard only supports up to ddr2 800mhz instead of 1066mhz.

So my question is will this be a problem? or will it just under clock?

[sulky_uk]

from what i remember to a similar mistake a friend made the mobo just ran it at the slower speed, which in my mind would make sense. If you havent unpacked it yet i would just send it back and say that you ordered the worng speed

[TeaLeaf]

Check for mobo bios updates too which sometimes increase the speed of ram that can be run.  Otherwise yes the RAM will simply underclock.

Not sure about returning it, slow speed memory is sometimes more expensive than 'current' high speed due to lower sales volumes, and the sticks you have can be used on a future machine.

TL.

[T-Bag]

As TL has said, it's usually fixed in a bios update. There's not much point returning it and then buying new stuff with the lower speed, it'll run at the same speed this stuff will and it will cost roughly the same. Also the cheaper stuff might have worse timings anyway so at the same clock speed the ram you've got might run faster.

[DarkAngel]

Great thanks guys

[Carr0t]

Check what voltage the Kingston is supposed to run at and whether you can up the voltage going to the RAM slots in your mobo BIOS. DDr2 800 default voltage is 1.8V. most overclocked RAM expects to get anything from 2.0V to 2.5V, and it'll tell you in the instructions for it what it should be.

I underclocked some DDR2 1066 to 800 Mhz a while back and had no end of problems until I pushed the voltage up to it's expected 2.1V (random crashes, failing to return from monitor power save etc etc). It would seem that even when running at stock speeds some memory still expects the extra voltage.

[BigFatCat]

Most performance RAM needs around 2.0-2.2v to operate even at rated specs.

My Ballistix 800 needs 2v to run at its intended speed. However, it will also overclock to 1000MHz at that voltage so there's no reason not to set your vDIMM to the voltage on the RAM's label and using RAM dividers clock it up to its normal speed. No need to underclock it.

My CPU FSB is 200, and the RAM divider is at 1.25, so it runs at 1000.

[Carr0t]

Aye, I was doing that. But since I jumped from 4GB to 8 i've had to drop back down a bit. Can't put the divider above 1:1.20 now without it refusing to boot, whereas before it was quite happy at 1:1.25 or even 1:1.5. I've had to O/C the CPU a bit by pushing the FSB up to get back towards my desired speed.

As a completely random aside, cos I noticed I had done a lower case r in one of my DDRs above, where has the 'edit post' button gone?

EDIT: It's on this post. Are you only able to edit posts that are the last one in a thread? Was that always the behaviour?