RAM compatibility question

F

ferrethouse

Geek Trainee
Hi folks,

This is the system I currently have...

HP Pavilion Media Center TV M7750n (Athlon 64 X2 Dual Core 2.6 GHz, 2 GB RAM, 400 GB HDD) Specs. Desktops Specifications.

Specifically, this is the RAM currently in the system...

RAMInstalled Size 2 GB / 4 GB(max) Technology DDR II SDRAM Memory specification compliance PC2-4200 RAM form factor DIMM 240-pin Upgrade rule (RAM) Max 4 x 1 GB module

And this is the processor and motherboard...

ProcessorType AMD Athlon 64 X2 5000+ / 2.6 GHz 64-bit processor Yes
MainboardChipset type NVIDIA GeForce 6150 LE Data bus speed 2000 MHz

So currently I have 2 gigs of PC2-4200 RAM. I'm looking to add another 2 gigs. Do I have to add PC2-4200 or can I add PC8500 or PC6400? What is the difference and would I see an advantage given my system configuration.

Thank you in advance.
 
ferrethouse said:
So currently I have 2 gigs of PC2-4200 RAM. I'm looking to add another 2 gigs. Do I have to add PC2-4200 or can I add PC8500 or PC6400?
Click to expand...
PC2 is DDR2 RAM. PC is DDR (1) RAM. DDR2 is faster than DDR1. So if your existing RAM chips work at DDR2 speed, and you add PC8500/PC6400 (DDR) you'll get lower performance because you're slowing everything down to the DDR1 speed (wich is much slower). You CAN however use DDR2 chips at a higher frequency. For example: You have PC2-4200. If you put PC2-4200 or higher (PC2-5800 for example), then you have the speed of PC2-4200 in all RAM chips. If you put a slower chip in it, then the speed is lowered to the speed of the slowest RAM chip, or some chips might not work at all.

So if you want to upgrade your RAM, then I would suggest to buy PC2-4200 RAM. So you won't have to pay more money for faster RAM chips that don't run at the maximum speed. Your motherboard has 4 DIMM slots, wich support a maximum of 1 GB each. You got 2 GB right now, so there are 2 DIMM slots still available. If you want more than 1 GB, then buy one RAM chip of 1 GB for the 3rd DIMM and another RAM chip of 1 GB for the 4th DIMM.
 
Thank you for the reply. Very informative. I'm probably better off jumping to 4 gigs at 4200 rather and ditching the current 2 gigs at 4200 and buying 2 new gigs at 8500? i.e. 4 gigs of 4200 is probably better than 2 gigs at 8500 correct?
 
ferrethouse said:
4 gigs of 4200 is probably better than 2 gigs at 8500 correct?
Click to expand...
No, 4200 and 8500 are speed frequencies. They don't have anything to do with the capacity. But all RAM chips work at the same frequency. The speed of PC2-4200 is limited to 4200. So if you put a PC2-8500 in it, the RAM speed has to be the same on all chips. So the system lowers the speed of the 8500 to 4200, because it is easier to lower the speed of a chip then increasing the speed above the speed limit.
 
One quick follow-up before I purchase the RAM. How do I know if my motherboard supports dual-channel RAM? Here is the motherboard specifications...

HP and Compaq Desktop PCs*-* Motherboard Specifications, A8M2N-LA (Nodus)*

It says this...

Four 240-pin DDR2 DIMM sockets
Supports PC 4200 (533 MHz) and PC2 5300 (667 MHz) DDR2 DIMMs
non-ECC memory only, unbuffered
Maximum HP/Compaq approved memory is 4 GB*

But it doesn't say anything about dual channel.

Thanks.

EDIT: I found this article...

AM 2 gains little from dual channel memory

That says that my processor gains very little from dual channel. So I guess I should save a few bucks and stick with single channel even though it looks like my processor supports dual channel.
 
RHochstenbach said:
For example: You have PC2-4200. If you put PC2-4200 or higher (PC2-5800 for example), then you have the speed of PC2-4200 in all RAM chips. If you put a slower chip in it, then the speed is lowered to the speed of the slowest RAM chip, or some chips might not work at all.
Click to expand...

I intend to purchase new motherboard that supports DDR400. But I was thinking about transferring the hardware from my old mobo into it, including the memory, which is slower - it`s DDR. So, there is a chance that the new mobo will not accept it?

(i`m sorry for not opening my own thread, but my question was similar. )
 
You currently have PC2-4200 DDR2 RAM. So when you want to buy a new motherboard, then you should look for the following: It needs to support DDR2-SDRAM and the speed PC2-4200 needs to be supported. When the new mobo supports that, then there is no problem.
 
RH said:
PC2 is DDR2 RAM. PC is DDR (1) RAM. DDR2 is faster than DDR1. So if your existing RAM chips work at DDR2 speed, and you add PC8500/PC6400
Click to expand...
i unfortunately slightly disagree

yes PC2 is DDR2 & PC is DDR1 and yes DDR2 is faster than DDR, however, PC8500/PC6400 do not exist, it should be PC2-8500/PC2-6400


Bs DDR speeds cheat sheet

RH said:
(DDR) you'll get lower performance because you're slowing everything down to the DDR1 speed (which is much slower).
Click to expand...
yes DDR is slower than DDR2, however 8500 & 6400Mhz RAM is DDR2

sorry RH, no offence

RH & anyone please feel free to check & correct me
 
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