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Need help with memory question please

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BlackHawk1

Joined
Jul 18, 2010
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Hi. I have a Dell Optiplex GX520 that currently has 2 sticks of DDR2, PC2 4200 @533mhz. The total memory is currently 1GB. There are just 2 memory slots on this motherboard. I ran PCWizard on this computer and it says that my motherboard has a FSB (front side bus) max support of 800mhz and a ram/memory max support of DDR2 667mhz.

I was thinking of getting some PC2 5300 @667mhz. I wanted to go with 2, 1GB sticks for a total of 2GB of ram.

I did see some people elsewhere saying that this computer can handle PC2 6400 @800mhz memory. Is this a fact? Is there any advantage or would it clock down to 667mhz since PCWizard says it supports a max of 667mhz? Or does the 800mhz FSB figure mean I can run the 800mhz PC2 6400 memory? I am confused on this. :(

If it would run the PC2 6400 @800mhz would I be wasting money? Let me know all you can. Thank you very much!
 
I don't think you could get 800mhz outta the ram as it will down clock to the board settings of 667mhz.
And thus, that will down clock to the current ram of 533mhz. So it appears you will be wasting money.
Because, when you match two different speeds of ram, the slower one is what is used.
 
Thanks for the reply. I appreciate it. I would be getting rid of the PC2 4200 @533mhz and going with nothing but either...

PC2 5300 @667mhz, or PC2 6400 @800mhz

I know it will handle the PC2 5300 @667mhz. My biggest concern is if it can handle (compatibility) and take advantage of the PC2 6400 @800mhz.
 
The difference in price between 667 and 800 Mhz set of RAM is like $3. Get the 800 Mhz for a few dollars more and give it a shot. Board specification and limitations are often different. PCWizard is probably report the boards recommended specs and not the actual limitation.

Also note that if the RAM runs 667 with a cas of 5, and you find a similar set at 800 with a cas of 6, speed will be nearly identical so you might as well go buy a cheese burger with the $3.
 
I think you should opt for 800mhz sticks. The board will just run at auto and you MAY be able to get better timings out of the ram @ 667 if it does "underclock" the sticks.
 
I would also make sure your BIOS is the latest one available.
 
you can get a 667 and overclock it. it will be able to go till 720 atleast. i have 667 transcend DDR2 jetRAM and mine is working at 720MHz.
 
You can't really overclock anything with a Dell Bios can you? Not the last time I tried. Maybe they have changed that.
 
that might be a problem. i hope it will not be a problem with a NEW BIOS
 
With some newer Dells I have had luck with ClockGen & Memset. Wish I could post some screenshots of it ...
 
The amount of effect it normally takes to remove/replace a BIOS on a pre-build from Dell is just not worth in in this case. You can get the same improvement in speed by just getting higher quality RAM with lower timing.

If I recall you may not be able to turn auto clocking off for the RAM, but I am sure he will ask if he has more trouble.
 
I want to thank everyone that replied! It is much appreciated.

I have the latest BIOS update for the Optiplex and I doubt Dell will ever release another one for it. I also have a Dell Vostro 400 with quad core... it has DDR2-SDRAM PC2-6400 (399 MHz) - [DDR2-800] according to PC Wizard. I guess I could take it out and put it in the Optiplex to see if it will work. How will I know if it is running at the proper specs or it down clocked? Thanks!
 
BlackHawk1 said:
I want to thank everyone that replied! It is much appreciated.

I have the latest BIOS update for the Optiplex and I doubt Dell will ever release another one for it. I also have a Dell Vostro 400 with quad core... it has DDR2-SDRAM PC2-6400 (399 MHz) - [DDR2-800] according to PC Wizard. I guess I could take it out and put it in the Optiplex to see if it will work. How will I know if it is running at the proper specs or it down clocked? Thanks!
Click to expand...

check the BIOS. If the BIOS don't say they are running at 400 Mhz this it is fine. If it says 333 Mhz, it got down clocked to the 667 DDR the original RAM was running at.
 
@BlackHawk

Did you see the 800mhz in the memory tab of CPUz www.cpuid.com? Check that out and see what values it's showing.
 
I will check on these things as soon as I get to that computer which will be in a few days. Thanks!
 
A Cheese Danish said:
I don't think you could get 800mhz outta the ram as it will down clock to the board settings of 667mhz.
And thus, that will down clock to the current ram of 533mhz. So it appears you will be wasting money.
Because, when you match two different speeds of ram, the slower one is what is used.
Click to expand...

Yeah, you need all ram the same speed or it uses the lowest speed of your rams.
 
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