I have a
HP Pavilion 516x Desktop PC
MOBO TriGem 2002052 (Glendale) --- According to HP Website
Celeron® CPU 2.40GHz

The HP website tells this about memory:
Memory type DDR
Memory speed PC2100/PC1600
Memory sockets 2 DIMMs (184 Pin)

I under stand the 184 pin but the speed and PC2100 I need help with.
I was looking at pqi POWER Series 1GB (2 x 512MB) 184-Pin DDR SDRAM DDR 333 (PC 2700) Dual Channel Kit System Memory - Retail from newegg. This seems pretty cheap at $69.99 at 1GB of RAM.

Also could you tell me what PC2100/PC1600 and PC2700 mean?
The part number on the memory in the computer now comes up as PC2700

What is the difference between DDR 333, DDR 400 and so on. Is this the speed in MHz?

Can you put as fast as memory as you want in any computer as long as it complies with DDR 184 Pin?
Will it just max out at the limitations of the MOBO or are there other considerations?

One more question please.
Are two sticks of 512MB any faster than using a single 1GB stick?

Thank you,

Mike

Yes, the pc2700 would work with your pc2100. The pc2700 would just be lowered to the pc2100 speeds. It would also work with pc3200 and maybe other higher clocked 184-pin modules.

As for the ddr333 and pc2100 terminology, the PCxxxx is the memory bandwidth. Like 2700 MB/s. this corresponds to the 333mhz clock speed. By using a 64-bit memory architecture 8 bits wide, you get the 8 * 333mhz = 2700MB/s.
Some of that is simplified from a guide at http://wiki.answers.com/Q/What_does_PC3200_stand_for

It can be kinda difficult to understand so I'd just assume to know they corrospond to each other even if you dont know how ;)

Oh yeah, and sometimes running 2 dual-channel sticks of ram can be faster, but that is mainly with fast ddr2 ram. I don't think you would see much of a difference with ddr. And that is a good price for a gig of ram.

Thanks,

I was reading another site about memory after posting and you could make a career out of memory module information!!! Never even reached the part about how DDR333 = PC2700!
I read the link you gave too.

64 Bits = 8 bytes

8bytes * 333MHz = 2700MB/s

The writing on my memory makes more sense now!
I was thinking of getting the fastest memory I could providing the price was only a couple $$ difference.
This was just the thought if I were to use it later in another computer.

The PC3200 is too big of a jump in price so I am going with the one I picked now that you have educated me.

Thanks for your help.

Mike

Did a quick check at crucial.com here is the link for your machine:

http://www.crucial.com/store/listparts.asp...l=Pavilion+516x

looks like the most ram that your machine can handle is 1 gig (2 x 512)

Your welcome. And like old fart said, that crucial tool is a great tool to help you find out exactly what ram you need.

I stand corrected!

They have PC3200 for the same price! $69.99 Go figure!

I know the MOBO will not take advantage of it, but if I ever move it to another one in the future that takes the 184 pin, I'll be that much further ahead.

I found the 1GB limit on the HP site, but what they didn't have was what I was about to ask you.

The crucial site showed me I could use the PC3200! That site is a keeper!

I wanted to get the most for my buck, but was worried about a conflict of a memory chip with too high speed rating!
The other thing crucial has that HP site does not. I can enter in a Gateway computer!!!!!

Thanks for the info.

Mike

Good job. Being future-proofed is always good.

Mad deals on newegg...

I don't know if that is a good idea though. I have mix and matched speeds of ram and worked fine, but I fried a friends motherboard once with a different stick. He had a stick of 128mb pc2700 in his computer. I put a stick of 256mb pc3200 in his opened slot and the computer fried and wouldn't turn back on . I would say go with what they recommend, so you don't have to shell out for a new motherboard.

I think its largely dependent on age and quality of the motherboard. I am actually mixing pc2700 and pc3200 ram on one of my computers and it is working perfectly.

With some older motherboards the compatibility of the RAM was trickier than it is today. Some motherboards didn't like double sided modules, and some wouldn't run on high density modules.

The thing to remember here is that the mixed RAM will only run as fast as the slowest module. If you mix a PC3200 and a PC 2100 the PC3200 module will underclock down to the PC2100.