How close do memory specs have to match when adding memory to system?

[bgc99]

I need to add memory to my parent's pc before upgrading the OS.

Mobo: M4A785TD-V EVO
Memory: (KINGSTON) 2x1GB KVR1333D3N9K2/2G (1333MHZ, 1.5V, CL9)

I wanted to add another kit like it has but it is discontinued. Which memory specs need to match precisely? Will a 1600/1.5/CL9 kit work? Since it has 2 1GB sticks, is it a problem to add 2 x 2GB for a total of 6GB or should I hadd 2x1GB?

Thanks,
BGC

 

[BonzaiDuck]

I need to add memory to my parent's pc before upgrading the OS.

Mobo: M4A785TD-V EVO
Memory: 2x1GB KVR1333D3N9K2/2G (1333MHZ, 1.5V, CL9)

I wanted to add another kit like it has but it is discontinued. Which memory specs need to match precisely? Will a 1600/1.5/CL9 kit work? Since it has 2 1GB sticks, is it a problem to add 2 x 2GB for a total of 6GB or should I hadd 2x1GB?

Thanks,
BGC

It might depend on which OS your parents are using. [I know an old lady in N. Carolina whose bank had informed her they "no longer support Windows XP" for online banking. It threw her into a tizzy. She'd had the computer since Windows 98.] For VISTA or later, there shouldn't be a problem going from 2GB to -- say -- 6GB.

Under certain circumstances, it's OK to mix kits, and these are the circumstances I would suggest:

1) The new kit is of the same make as the old one
2) Both kits have the same voltage spec
3) In their SPD/JEDEC data, both kits overlap in their basic timings or latency specs
4) You don't plan on overclocking the system (not a hard and fast rule, but if you're going to do such a thing, you shouldn't be thinking of any hardware complications)

On the other hand, if you're starting out with a 2x1GB kit, why not just replace it entirely with a 2x2GB or even a 2x4GB kit? Of course, it depends on the system board, and as I said, the OS. But memory in kits of that amount is pretty cheap -- provided it meets the motherboard's specs.

 

[lightningbaron]

When in doubt, you can try crucial.com, select the make and model.