Help on selecting DDR2-533 or DDR2-800 memory?

dwlovell

Distinguished
Feb 9, 2007
1
0
18,510
I have a DELL where I cannot overclock and cannot even change the latency timings, I am pretty sure it uses whatever the memory says in SPD.

So its a XPS 410 and I have a Core 2 Duo 6700. All of the Core 2 Duo line currently are 1066 FSB which means that I believe DDR2-533 should be the ideal memory. I have read that faster memory (667 and 800) will just run in 533 mode since thats half the FSB and the DELL bios doesnt support the async modes with different ratios.

Secondly, I have heard the SPD in each memory is set by the JEDEC recommended for each DDR mode. So 533 is 4-4-4-10 and 800 is 5-5-5-12. If you buy a DDR800 and it sais 4-4-4-9, that means it supports it, but you MUST override it in BIOS because the SPD will always report 5-5-5-12 for 800mhz memory.

So I just placed an order for DDR800 memory with timing of 4-4-4-12 for my system, but my question is wether I wasted my money if the DELL is only going to run it at DDR533. Additionally, will this mean the dell will run it at 5-5-5-12 since thats the SPD on the chip, whereas if I bought simple DDR533 memory, the SPD would be set lower and would actually run faster on my system.

Any thoughts/expertise on this issue?

-David
 

SuperFly03

Distinguished
Dec 2, 2004
2,514
0
20,790
It will depend on what the motherboard supports. If the motherboard supports DDR2 800 (which it should) then it *should* default to the highest supported speed for both the mobo and RAM, in this case 800.

I've had a Dell before and you're right you can't OC them but you can add any type of RAM to it. I would really expect it to work fine with the new RAM. Check it out with CPU-Z when you install the RAM.

Best of luck
 

Syntonic

Distinguished
Jan 15, 2007
93
0
18,630
Didn't you answer your own question?

"I have a DELL where I cannot overclock.... All of the Core 2 Duo line currently are 1066 FSB which means that I believe DDR2-533 should be the ideal memory. I have read that faster memory (667 and 800) will just run in 533 mode since thats half the FSB and the DELL bios doesnt support the async modes with different ratios."

If you really can't set the timings yourself, then yes, you somewhat screwed yourself over there but the DDR2-800 should be able to run even tighter timings than the lower rated RAM. Then again, my brain hasn't been working correctly all day today so I could be very very wrong.
 

mikeny

Distinguished
Aug 6, 2006
1,469
0
19,310
I had ddr2-533 for my C2D e6300 and got yelled at for not getting faster memory sticks. So I went up to ddr2-675 (4GB). I dont OC. My mobo is reading the 675 speed.
 

SuperFly03

Distinguished
Dec 2, 2004
2,514
0
20,790
I had ddr2-533 for my C2D e6300 and got yelled at for not getting faster memory sticks. So I went up to ddr2-675 (4GB). I dont OC. My mobo is reading the 675 speed.

You are supposed to go either 533 or 800 if you don't oc, not 667. If you OC, that brings to life a whole crap load of other factors.

Source

It's an elongated explanation but very interesting.

4GB of RAM, wth do you do with all that? lol :wink:
 

mikeny

Distinguished
Aug 6, 2006
1,469
0
19,310
SuperFly03 said:
4GB of RAM, wth do you do with all that? lol :wink:



sit back and relax :)

Yupp I know either 533 or 800 but I was told by many that 675 is good since I dont OC and if I do in the future I have some space. But again i dont see myself Ocing anyway. I was aksing around about going higher than 533 and everyone said yes. So i went with 675.