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View Full Version : CORSAIR Misleads you and twists truth in naming scheme...


cvearl
06-05-03, 01:32 AM
When I picked up my new ASUS P4C800, I wanted to ensure I had a good pair of DDR400 aka PC3200 RAM. Corsair i widely known as a good brand. And it is! Therefore, after reading at thier website that my "XMS PC3200 CAS 2" memory can do 400Mhz at CAS 2, I picked it for my mobo's companion. My Sandra scores are good but lower than those of the reviews I have read. Those reviewers are getting 4900-5000 mb/s and I find that they were using PC3500 CAS 2 or Low latency PC3200 much of the time. I figured I would not need that based on claims at Coprsairs site.

Problem is that I am getting 4483 mb/s. Respectable but not what the memory is supposedly capable of. Using CPU Z utility, I find that my RAM is at 2.5-3-3-8 when BIOS is set to "By SPD". The CORSAIR web site says the RAM is rated for 2.3.3.6. Funny thing is that if I set this manually via the BIOS, the RAM scores go up very little to 4505 or so. Huh?!?! While I get this small boost in performance for memory bandwidth, my CPU scores in Sandra drop by 10-15%! This indicates the RAM is having trouble relaying data to the CPU and back at those advertised timings.

To prove the point further, here is SPD programming in the modules as reported by CPU Z. Which by the way does not lie about this. This is data in the SPD of the modules themselves...

CPU-Z version 1.18
Memory Modules Serial Presence Detect (SPD)

Module #0
Memory type DDR-SDRAM
Manufacturer (ID) Corsair (7F7F9E0000000000)
Size 256MBytes
Max bandwidth PC3200 (200MHz)
Part number CMX256A-3200C2
Max frequency @CAS#2.0 166MHz
Max frequency @CAS#2.5 200MHz

Module #1
Memory type DDR-SDRAM
Manufacturer (ID) Corsair (7F7F9E0000000000)
Size 256MBytes
Max bandwidth PC3200 (200MHz)
Part number CMX256A-3200C2
Max frequency @CAS#2.0 166MHz
Max frequency @CAS#2.5 200MHz

This means that it can only do CAS 2 properly when run as DDR333 or 333Mhz (166x2).

How is that they can sell this as CAS 2 DDR400? It's a crock. I've had the RAM too long to return it for PC3500 and that sucks! Some may think I am being picky but I look at it this way. If I buy a LEXUS or MERCEDES, I want a LEXUS or MERCEDES. Not almost a LEXUS or MERCEDES. I paid for what they advertised and got a step down. This is misleading. Sure if you look at it like this...

CMX256A-3200C2 can do 400Mhz (but at CAS 2.5) and do CAS 2 (but at 333Mhz) therefore we can call it 400Mhz CAS 2 memory. Can you say Bull$hiet! Sure, I knew you could.

Thought you all should know.

Charles.

PsychoSy
06-05-03, 03:10 AM
Probably talking out my ass here, but have you tried going into the BIOS and disabling any options that talk about "Spread Spectrum" and stuff?

Options like these sacrifice performance for stability.

Red Dog
06-05-03, 07:49 AM
you dont have to return it to the place of purchase, corsair carries a lifetime warranty to perform at spec timings.

go to corsair's site, If the part fails Corsair's test, it will be replaced by an equivalent (or better) part that passes the test.

http://www.houseofhelp.com/forums/showthread.php?threadid=6288

dont tell them you only get 44xx mbs, pc 3200 is rated at 3200 mbs. just tell them your spd values are not in spec and you cant run 200.

good luck.

|JuiceZ|
06-05-03, 12:18 PM
I second Red Dog's suggestion :type:

cvearl
06-05-03, 01:46 PM
You have to realize that dual channel has nothing to do with it. The RAM is running the same load in single or dual. Its the memory controller that is working harder. Being rated at 3200 MB/s theoretical means that in a dual channel config, that's 6400 mb/s. I know that you never reach this but the 875 and 865 chipset can hit 4900-5000 without any tweaking as long as the memory is fast and stable enough. They say that this XMS stuff I bought is certified to run at 400Mhz at CAS 2. But it turns out not both at the same time. That's whats wrong and misleading. The SPD values are put there by the engineers to tell the motherboard what timings to use in what circumstances. IE: 166Mhz (DDR333 effective) you can run at 2.0 Latency. At 200Mhz (DDR400 effective) you can run in 2.5 Latency. When based on thier description of the RAM, it should be CAS 2 at 400Mhz. Thier XMS PC3500 (DDR466) is CAS 2.5 at 233Mhz but at CAS 2 it is rated in the SPD for DDR400 speed (200Mhz). This says to me that they need to sell the current PC3500 as PC3200 to be in lines with thier claims for the PC3200 stuff. Dual Channel has nothing to do with it. Dual channel is all memory controller. It is not pushing memory any harder. In single channel mode I am still defaulting to 2.5-3-3-8 and that is what SPD is set to in 200Mhz mode.

I can in fact run at thier 2-3-3-6 setting in DDR400. And I get slightly better memory scores but then I get lower scores by 10-15% in CPU. That is an instability issue on this memory and why it is only rated at 2.5 when in DDR400 mode.

Lastly, there are guys out there with HyperX PC3200 getting 4900+ mb/s in Sandra at default SPD in the BIOS and no tweaking. Being that I liked Corsair I went with that instead thinking that at this price it should be the same. "Fastest memory in the world". Ya right.

Charles.