Confusing Ram Numbers

Fakum · Rated PG Joined: 30 Sep 2007 Posts: 9 Location: USA

I spent the evening trying to brush up on what all the numbers mean for purchasing memory. I am pretty compfortable with the Cas Latency and the other numbers such as â€œ4-4-4-12â€ (lower is better is my understanding) What I donâ€™t have a handle on is the other numbers e.g.

OCZ Platinum Revision 2 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory

DDR 800, what do I make of this number â€œ(800)â€? Do I try to match this with the Motherboard Specs if it says â€œMemory Standard
DDR2 533/667/800 and up to 1200 MHzâ€

And what about â€œ(PC2 6400)â€ What does this all mean?

I am putting a Christmas list together to do an upgrade,(budget = $1000) the following components are what I am considering for purchase. There is so much ram out there, it will make your head spin. This aspect seems to be the most difficult for me to figure out. I want to get the most bang for my buck. I am using this new PC for gaming, I donâ€™t really dabble in overclocking, but it would be nice to go for it. Here is the list so far.

MOBO option 1:EVGA 122-CK-NF68-A1 LGA 775 NVIDIA nForce 680i SLI ATX Intel Motherboard

MOBO option 2: GIGABYTE GA-P35C-DS3R LGA 775 Intel P35 ATX Intel Motherboard

MOBO option 3: GIGABYTE GA-P35-DS3R LGA 775 Intel P35 ATX Intel Motherboard REV 2

CPU: Intel Core 2 Q6600 GO stepping

Video: EVGA NVIDIA GeForce 8800 GTS 640MB 16X PCI Express

Power Supply ADD-ON: Thermaltake W0099RU PurePower Power Express 250W Power Supply

**Doctor Feelgood** · Posted: Sun, 07 Oct 2007 09:01:57 Post Subject:

That 800 number is the speed of DDR2 memory in MHz. Yes, you match it up to the motherboard's speed rating specifications.

The PC2-6400 number represents the bandwidth, and it is how most manufacturers advertise their DDR2 (and DDR or DDR3). In my opinion it makes you remember an extra bit of information just to recognize the speed.

Some examples:

PC2-5400 is 667 MHz
PC2-6400 is 800 MHz
PC2-8500 is 1066 MHz

PC-3200 is 400 MHz DDR
PC3-10666 is 1333MHz DDR3

Fakum · Rated PG Joined: 30 Sep 2007 Posts: 9 Location: USA

I am still a bit confused, sorry. You say "That 800 number is the speed of DDR2 memory in MHz." I am with you so far,,, you go on to say"
PC2-6400 is 800 MHz "represents the bandwidth. Am I confusing speed with Bandwith? I thought they were both the same? thanks for your feedback, it is most appreciated

**Doctor Feelgood** · Posted: Sun, 07 Oct 2007 09:31:41 Post Subject:

They are different. Speed is the frequency of the memory, and bandwidth is how fast it communicates.

This Wikipedia page gives a better differentiation than I could come up with...

http://en.wikipedia.org/wiki/Memory_bandwidth

Plus, it gives the general equation used to get from speed to bandwidth.

addicted · Rated PG Joined: 16 Nov 2007 Posts: 1

Thanks for the link. Very usefull indeed.