Memory underclocking question...

PaulTa

Distinguished
Feb 3, 2007
25
0
18,530
Hey guys,

I wanted to know, if I buy PC8000 memory and the most my mobo supports is 6400, can I underclock the memory from 1000mhz to 800mhz and run it stable?

The mobo is Intel D975XBX2 and the memory is buffalo firestix PC8000

Thanks for any advice and comments in advance.

Regards,
Paul
 

memorymaster

Distinguished
Feb 15, 2007
42
0
18,530
First of all, any memory module you buy over 6400 CL 5 is overclocked product. So most memory companies ( I don't know much about buffalo tho) have the JEDEC standard programed in their modules as 6400 CL5 so the system will boot up for people that have limitations to their motherboards. So, if buffalo programs their memory at 6400, u should have no problem booting up.

However, if buffalo only programs their modules at 1000 MHz, then you would need to use another module programed at 800 MHz to boot the system into the bios. From there, you would just manually set the memory to 800 MHz, and then you could boot up at your buffalo modules.
 

ak47is1337

Distinguished
Jan 30, 2006
1,830
0
19,780
Master is correct. I would recommend overclocking your FSB on your processor and moving the multiplier down to get full effect of your DDR2-1000 RAM.
 

RJ

Distinguished
Mar 31, 2004
655
0
18,980
Hey guys,

I wanted to know, if I buy PC8000 memory and the most my mobo supports is 6400, can I underclock the memory from 1000mhz to 800mhz and run it stable?

The mobo is Intel D975XBX2 and the memory is buffalo firestix PC8000

Thanks for any advice and comments in advance.

Regards,
Paul
Get CPU-Z and see what the settings are under the SPD tab. For example, I've got DDR2-800 memory. In CPU-Z it shows the SPD settings for 400 mhz @ 5-5-5-18-23. For 266 mhz(533), it shows 4-4-4-12-16. For 200 mhz(400) it shows 3-3-3-9-12. That'll show you the timings that SHOULD WORK if you underclock your memory. Having DDR2-1000 would be a nice fallback, should you get the "overclocking bug", which is really easy with the Core2 Duo. Should you set the FSB to 400 mhz, setting the memory to its "667" setting should give you DDR2-1000, just what you'd have. 8)

I'm kinda stuck @ 450 mhz, because my memory is currently OC'ed to DDR2-900. I don't know how much headroom the memory has left. Having some DDR2-1000 would be nice to have to see how much the rest of my sytem has left.
 

PaulTa

Distinguished
Feb 3, 2007
25
0
18,530
So if the mobo only supports a maximum of 800mhz, and I have 1000mhz memory, hopefully the SPD sets the memory at a lower timing so I can then boost it to 800mhz at lower latencies than standard 800mhz memory?

And if the SPD doesn't set it at a lower speed, I'll have to use another memory module to adjust something in the BIOS. What exactly is it I adjust?

Thanks for your help guys.

Regards,
Paul
 

PaulTa

Distinguished
Feb 3, 2007
25
0
18,530
This post may be helpful: http://forumz.tomshardware.com/hardware/modules.php?name=Forums&file=viewtopic&p=1249881#1249881

More than helpful. If you ever need any help with PSU's, stop by JonnyGuru.com and we'll set you up. PM me for a PSU deal that ought to brighten your day (I know some people who know some people who have a deal with some resellers :wink: ).

So basically buying Buffalo Firestix 1000mhz when my mobo is only rated for 800mhz RAM max means that I'll have to manually adjust such things in the BIOS, which wont be a problem since most mem. manufacturers put uber-conservative timings and speed in their SPD chips.

However, if the SPD timings are still higher than 800mhz, I have no idea what to do. Hopefully that isn't the case though, and it probably isn't.

I'm being edumacated here... :p
 

PaulTa

Distinguished
Feb 3, 2007
25
0
18,530
I was hoping for some clarification on that last point guys, since I will probably be purchasing RAM tonight. I don't want to purchase RAM that will in no way work with my mobo, which is why I'm nagging.

Thanks in advance,
-Paul
 

memorymaster

Distinguished
Feb 15, 2007
42
0
18,530
Sorry for getting back to you so late..... if you do have an old memory module, i am pretty confident that the 1000 MHz buffalo module will work with your motherboard (unless the module itself turns out bad, which about 10% do, and then you have to return it for a new one).

So, if the system does not boot up at all with your new memory module in, then you would put your old one back into the board. You would then go to the bios, and depending on what type of bios you have, you want to go into either the advance chipset menu, the jumper free configuration menu, or something similar. You want to manually change your dram frequency from auto to ddr2-800. (You can always then reduce the dram voltage manually (probably to 1.8V if you are doing certain timings such as 5-5-5-15)).

The system then should boot up with your new module inside.... So, if i were you, I would get the memory module and then see if the system boots up right away first without adjusting the bios...