Thursday, September 18, 2008

Counterfeit Corsair High Performance XMS RAM

Ok, make a guess. Which of the two following DIMMs are fake.



Now, recently, I bought a Corsair Ultra Performance XMS 512MB DDR400 RAM from lelong.com.my (a local ebay clone) because I already have an existing Corsair RAM and getting another one should give my aging machine a performance boost with more memory and faster dual channel memory bandwidth.

I was pretty excited when I receive the parcel a few days ago. I plugged it into the mainboard and it seems to work. It passes the memtest86+. However, I notice something fishy when the memory speed shows 333MHz when it should be 400MHz.

I booted into the old rusty WinXP (linux lshw does seems to show much useful info), and I ran PC Wizard. The following is part of the report from PC Wizard.


>> Information EEPROM (DIMM1)
Manufacturer : Unspecified
Part Number : CMX512-3200C2
>> Serial Number
Type : DDR-SDRAM PC3200 (200 MHz)
Size : 512 Mb (2 rows, 4 banks)
Module Buffered : No
Module Registered : No
Width : 64 bits
Error Correction Capability : No
Max. Burst Length : 8
Refresh : Reduced (.5x)7.8 µs, Self Refresh
Voltage : SSTL 2.5v
Supported Frequencies : 166 MHz, 200 MHz
CAS Latency (tCL) : 2 clocks @166 MHz, 2.5 clocks @200 MHz
RAS to CAS (tRCD) : 3 clocks @166 MHz, 3 clocks @200 MHz
RAS Precharge (tRP) : 3 clocks @166 MHz, 3 clocks @200 MHz
Cycle Time (tRAS) : 7 clocks @166 MHz, 8 clocks @200 MHz
>> Information EEPROM (DIMM3)
Manufacturer : Kingston
Part Number : K
Serial Number : 8908BA99
Type : DDR-SDRAM PC2700 (166 MHz)
Size : 512 Mb (2 rows, 4 banks)
Module Buffered : No
Module Registered : No
Width : 64 bits
Error Correction Capability : No
Max. Burst Length : 8
Refresh : Reduced (.5x)7.8 µs, Self Refresh
Voltage : SSTL 2.5v
Supported Frequencies : 133 MHz, 166 MHz
CAS Latency (tCL) : 2 clocks @133 MHz, 2.5 clocks @166 MHz
RAS to CAS (tRCD) : 3 clocks @133 MHz, 3 clocks @166 MHz
RAS Precharge (tRP) : 3 clocks @133 MHz, 3 clocks @166 MHz
Cycle Time (tRAS) : 6 clocks @133 MHz, 7 clocks @166 MHz


As you can see at DIMM 1, the CMX512-3200C2 is my existing black Corsair DIMM and the other at DIMM 3 is a Kingston DDR PC2700!! I was like WTF!!? I don't mean Kingston is bad (I never had problems with my mum's machine), but I was expecting a high performance type and what I got was a standard Kingston value type.

So with a little searching on the web, I found out that all Corsair memory modules should have a holographic sticker with its model number, speed and other details as shown below for my original 512MB stick.



The Kingston RAM with a Corsair heatspreader is as below.


I am still in the process of negotiation with the seller for a refund or exchange. It seems that he also does not realize that, I would be nice to believe that it is an honest mistake as he is still willing to negotiate.

The black Corsair module has been giving me solid performance and stability for the last 5 years. So next time, I'll be smarter to make sure to check for the holograhic sticker when you purchase Corsair DIMMs.

BTW, I also found a pretty good "webinar" on memory basics by Corsair. Even for people familiar with computer hardware, this should be a pretty good refresher. http://www.corsairmemory.com/memory_basics/index.html


UPDATE: The seller agreed to exchange for a pair of Kingston 2 x 512MB Hyper-X memory for a little extra money. I got the item and this time they are real.
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