Upgrade RAMemory

[conquest]

Hail good citizens !

Configuration:

Dell Optiplex 755SFF
C2D E8400
2x1GB 667Mhz Kingston
WD 160GB
HD 2400 XT

Question: I would like to upgrade RAMemory to 4GB (maybe 8) and i need some directions, recommendations...As You can see i have 2x1GB modules and i was wandering is it better to buy 2x2GB 667Mhz or 800Mhz modules. At the moment FSB:RAM ration is 1:1.
I did some test but with a single module of 800Mhz and 600Mhz.What is a better?

Test1:
1GB 667
Memory:
Read 4767MB/s Write:5065MB/s Copy:4011MB/s latency:82.2ns 1:1
1GB 800
Read 5508MB/s Write:5804MB/s Copy:3980MB/s latency:82.6ns 12:10
2GB 667
Read 6270MB/s Write:6898MB/s Copy:5745MB/s latency:79.0ns 1:1

 

[skaz]

What's your OS?

Assuming you have a 64bit OS. And depending on what you do on your computer and depending on current prices for your type of ram needed I would say 4 GB is sufficient. But if you find that to bump up to 8GB isn't much more in cost then I would shoot for the 8GB.

EDIT: Again depending on price difference between the two I would go for 800Mhz modules.

 

[jaquith]

Welcome to Tom's Forum!

Hmm...Good, me, that's for you to decide

Synthetic vs Real World are two different things, Real World DDR2-800 vs DDR2-667 is 1%~3%. Next, Dell uses an OEM BIOS so adjusting DRAM Frequency, CAS Timings, etc might be a problem. To access >4GB of RAM a 64-bit OS is required otherwise 32-bit limits you to 4GB (3GB~3.5GB usable).

Specs - http://support.dell.com/support/edocs/systems/op755/en/UG/HTML/sff_spec.htm
Memory
Type 667-MHz or 800-MHz DDR2 SDRAM

I would purchase 2 matching kits of CT767881 DDR2-800 CAS 6 -> http://www.crucial.com/store/listparts.aspx?model=OptiPlex%20755%20Series%20(Desktop%20Mini-Tower%20and%20Small%20Form%20Factor)&Cat=RAM

 

[conquest]

Wow, thanks for quick answers folks !

I know about OS memory limitation, do not worry about that. I'm going to install 64bit W7. I use comp. for picture editing (Photoshop) some video editing, games...etc. Here in my place price is almost the same 667 or 800 (24euro 2GB), since it is easier to find 800 modules.
Just wandering which memory will give better performance.

 

[skaz]

Wow, thanks for quick answers folks !

I know about OS memory limitation, do not worry about that. I'm going to install 64bit W7. I use comp. for picture editing (Photoshop) some video editing, games...etc. Here in my place price is almost the same 667 or 800 (24euro 2GB), since it is easier to find 800 modules.
Just wandering which memory will give better performance.

If price is the same then defiantly go with 800Mhz and if your working with large pictures in photoshop with other programs in the background then shoot for 6-8GB. Never hurts to "try" and future proof if the price is right. Good luck mate! =)

 

[jaquith]

Whichever's cheapest. If you actually are running at 400MHz per CPU-z Memory tab (800MHz factoring in Double Data Rate) then sure the DDR2-800.

 

[conquest]

Whichever's cheapest. If you actually are running at 400MHz per CPU-z Memory tab (800MHz factoring in Double Data Rate) then sure the DDR2-800.

C2D E8400 has 1333Mhz FSB and i think 677Mhz memory match the 1:1 ratio not 800Mhz. Am i right? Do we think the same?

 

[jaquith]

333.33 FSB x 9 CPU Multiplier = 3.00 GHz. It's a 5:6 ratio (333.33 : 400.00) ; DDR2-800
333.33 FSB x 9 CPU Multiplier = 3.00 GHz. It's a 1:1 ratio (333.33 : 333.33) ; DDR2-667

The BIOS automatically will select a 1:1 JEDEC encoded 'SPD' in either the DDR2-667 or DDR2-800. Don't confuse maximum frequency with actual running frequency. Therefore, as I recommended get whichever's cheaper.

 

[conquest]

333.33 FSB x 9 CPU Multiplier = 3.00 GHz. It's a 5:6 ratio (333.33 : 400.00) ; DDR2-800
333.33 FSB x 9 CPU Multiplier = 3.00 GHz. It's a 1:1 ratio (333.33 : 333.33) ; DDR2-667

The BIOS automatically will select a 1:1 JEDEC encoded 'SPD' in either the DDR2-667 or DDR2-800. Don't confuse maximum frequency with actual running frequency. Therefore, as I recommended get whichever's cheaper.

Thanks for explanation. So i shouldn't worry about this ratio...

 

[jaquith]

Slower is not a problem, faster is. RAM has several JEDEC 'SPD' encoded, for example on an LGA 1366 DDR3-1066 is the default 'SPD' if I install DDR3-2000 and look at the actual Frequency it's running I'd see DDR3-1067 or on CPU-z 533MHz.

Therefore, the DDR2-800 on a default 'SPD' of DDR2-667 I'd see DDR2-667 or 333MHz.

Example note the different 'SPD' encoded in DDR3-1333:

Therefore DDR2-667 or DDR2-800 your pick.

Good Luck!