XMS Qualification and Testing

[RAM GUY]

XMS Qualification and Testing Updated 6-06-2006

Corsair has developed a methodology in-house for developing, qualifying, and testing memory for use in over clocking applications. Some common questions about this process are answered below, and details are given for testing for specific XMS product families.

Q: What does XMS mean, and what is the idea behind it?

A: We have taken to heart a few facts that over clockers have known for years:
1) Many integrated circuits are capable of operating much faster than their specified speed
2) Standards organizations by their very nature have a difficult time keeping up with market changes.

XMS, or eXtreme Memory Speed, is the process that Corsair uses to take ICs rated at one speed and verify/guarantee their operation at another speed. Since specifications have not been generated to accurately specify operating parameters, Corsair gives these parts an XMS rating. For example, since PC2400 does not exist according to any valid standards institution, Corsair parts are called XMS2400.

Q: How do you verify operation at the XMS speed?

A: In a nutshell, through extensive evaluation in our lab. In order to offer an XMS module, a RAM must be found which can run with adequate stability in multiple platforms at the XMS-rated speed. Testing is done using both Corsairs’ stress-testing fixture, as well as by running common benchmarks, applications programs, operating systems, and games. Parts are evaluated over voltage and temperature extremes to monitor stability. No XMS part is released until all criteria are met.

Q: How do you guarantee operation at the XMS speed?

A: XMS parts are a speed screen of Corsair's standard parts. They are 100% tested at the XMS-rated speed; parts that fall out of this test are tested at the standard rated speed. For example, XMS2400 modules are 100% tested at 300 MHz. Parts that do not meet this speed grade are then tested at PC2100. Specific testing parameters for various XMS products are given below.

Q: How do you program the SPD of XMS parts?

A: Programming the SPD of our XMS parts is a bit problematic. The industry-standard specifications for the SPD values of XMS parts are often not yet defined by JEDEC (the appropriate standards organization) when the parts are introduced. In order to maintain compatibility with the multitudes of motherboards and BIOS revisions out there, the SPD values are programmed at the fastest available parameters defined by JEDEC. The SPD values are defined in the matrix below. Note, though, that in ALL CASES the Corsair part number (which contains the XMS speed grade) is programmed into the SPD as well.

Dont see your module or speed grade listed please check Archive XMS Settings

XMS Specification SPD Values
XMS2700C2 JEDEC PC2700 values
XMS3200 JEDEC PC3200 values
XMS3200C2 JEDEC PC3200 values
XMS3200XL Custom values
XMS3500LLPro Custom values
XMS4000 Custom values for PC3700*
XMS4400 Custom values for PC3700*
XMS4400C25 Custom values for PC3700*

DDR2
DDR2 XM2S4300C3 Custom values for PC2-4300C3
DDR2 XM2S5400 Custom values for PC2-5400
DDR2 XM2S5400UL Custom values for PC2-5400UL
DDR2 XMS2-5400C4 Custom values for PC2-5400C4
DDR2 XM2S6400C3 EPP + JEDEC Values for PC2-6400C5
DDR2 XM2S6400C4 EPP + JEDEC Values for PC2-6400C5
DDR2 XM2S6400 JEDEC Values for PC2-6400C5
DDR2 XM2S8000UL Custom values for PC2-8000UL
DDR2 XM2S8500/C5 EPP + JEDEC Values for PC2-6400C5

* We do not expect PC3700 to ever be a ratified JEDEC specification; the values entered are based on what we would expect them to be.

Q: My XMS module does not work at the rated speed in my system. Why not?

A: There are many reasons why this can happen. Let me outline a few of them:

1) There are lots of motherboards out there, and we can only realistically evaluate/qualify a handful. You may have a motherboard that simply does not overclock well.
2) There is interaction between specific RAM manufacturers and specific motherboard manufacturers. Thus, for example, while EPoX boards might work best with RAM vendor A, Soyo boards might work better with RAM vendor B. Corsair strives to find the RAM that works most universally.
3) Other system components may not be overclockable. This may include the processor, chip set, PCI bus, IDE channel, etc.
4) The demands of today’s high end graphics cards and GHz processors the quality of your power supply has become increasingly import******** Make sure you power supply make and model is approved by your motherboard manufacturer and/or your CPU manufacturer.

There are many sites on the web which can give you more reasons, tell you which boards are best for overclocking. To get an idea, go to your favorite search engine and search for "overclocking guide".

Q: I do not see the specific part that I have IE: XMS3200LLPT, why not? And what is the idea behind a slightly different part#?

A: The PT at the end of the part# in this case CMX512-3200LLPT indicates the color of the heat spreader, and would be a cosmetic change! This has no bearing on the memory or settings only the color.
Please see What does C2, LL, PT, R or RE stand for in the part#? Or Archive XMS Settings


*Important Note* Unless stated otherwise, all testing is done with only one module at a time.

Testing parameters for XMS2700 CAS 2:

CMX512-2700C2 Data Sheet
CMX256A-2700C2 Data Sheet
Motherboard make and model: EPoX EP-8K3A and/or Asus P4S533 and/or EPoX EP-8K5A
DRAM Timing (overrides SPD values): Manual
System Performance: Normal
SDRAM Bank cycle time (or tRAS): 6
SDRAM Bank Interleave: 4
SDRAM Row Precharge (tRP): 3
SDRAM RAS-to-CAS Delay (tRCD): 3
SDRAM CAS Latency: 2
Command Rate: 1T
All other settings are motherboard defaults.



Testing parameters for XMS3200:

CMX512-3200 Data Sheet
CMX256A-3200 Data Sheet
Motherboard make and model: Asus P4C800/-E and/or DFI INFINITY I865/I875 and/or Asus A7N8X and/or ABIT IC7 Max3.
DRAM Clock: 200 MHz
DRAM Timing (overrides SPD values): Manual
System Performance: Normal
SDRAM Bank cycle time (or tRAS): 8
SDRAM Bank Interleave: 4
SDRAM Row Precharge (tRP): 3
SDRAM RAS-to-CAS Delay (tRCD): 3
SDRAM CAS Latency: 3
All other settings are motherboard defaults.


Testing parameters for XMS3200C2:
CMX1024-3200C2 Data Sheet
CMX512-3200C2 Data Sheet
CMX256A-3200C2 Data Sheet
Motherboard make and model: Asus P4C800/-E and/or DFI INFINITY I865/I875 and/or Asus A7N8X and/or ABIT IC7 Max3.
DRAM Clock: 200 MHz
DRAM Voltage: 2.7X Volts
DRAM Timing (overrides SPD values): Manual
System Performance: Normal
SDRAM Bank cycle time (or tRAS): 6
SDRAM Bank Interleave: 4
SDRAM Row Precharge (tRP): 3
SDRAM RAS-to-CAS Delay (tRCD): 3
SDRAM CAS Latency: 2 (2.5 on AMD platform)
All other settings are motherboard defaults.

Testing parameters for TWINX3200C2:
TWINX2048-3200C2 Data Sheet
TWINX1024-3200C2 Data Sheet
TWINX512-3200C2 Data Sheet
Motherboard make and model: Asus P4C800/-E and/or DFI INFINITY I865/I875 and/or Asus A7N8X and/or ABIT IC7 Max3.
Each pair is tested and packaged together using the following settings:
DRAM Clock: 200 MHz
DRAM Voltage: 2.7X Volts
SDRAM CAS Latency: 2T (2.5 on AMD platform)
SDRAM RAS to CAS Delay (tRCD): 3T
SDRAM Row Precharge (tRP): 3T
SDRAM Active to Precharge Delay (tRAS): 6T
SDRAM Bank Interleave: 4 Bank
All other settings are motherboard defaults.


Testing parameters for XMS3200XL:

CMX512-3200XL Data Sheet
Motherboard make and model: Asus P4C800/-E and /or Asus A7N8X
DRAM Clock: 200 MHz
SDRAM VDIMM: 2.75
SDRAM CAS Latency: 2T
SDRAM RAS to CAS Delay (tRCD): 2T
SDRAM Row Precharge (tRP): 2T
SDRAM Active to Precharge Delay (tRAS): 5T
SDRAM Bank Interleave: 4 Bank
All other settings are motherboard defaults.


Testing parameters for TWINX3200XL:

TWINX1024-3200XL Data Sheet
Motherboard make and model: Asus P4C800/-E and/or Asus A7N8X
Each pair is tested and packaged together using the following settings:
DRAM Clock: 200 MHz
SDRAM VDIMM: 2.75
SDRAM CAS Latency: 2T
SDRAM RAS to CAS Delay (tRCD): 2T
SDRAM Row Precharge (tRP): 2T
SDRAM Active to Precharge Delay (tRAS): 5T
SDRAM Bank Interleave: 4 Bank
All other settings are motherboard defaults.

Testing parameters for TWINX3500LLPro:
TWINX2048-3500LLPro Data Sheet
Motherboard make and model: Asus A8N-SLI Premium
Each pair is tested and packaged together using the following settings:
CPU External Frequency: Manually set to 217MHz
DRAM Clock: Manually set to 1:1 or 400MHz
SDRAM CAS Latency: 2.0T
SDRAM RAS to CAS Delay (tRCD): 3T
SDRAM Row Precharge (tRP): 2T
SDRAM Active to Precharge Delay (tRAS): 6T
SDRAM Bank Interleave: 4 Bank
SDRAM VDIMM: 2.75
Command Rate 1T
All other settings are motherboard defaults.
Maximum recommended VDIMM: 2.9



Testing parameters for XMS4000:

CMX512-4000 Data Sheet
CMX256A-4000 Data Sheet
Motherboard make and model: Asus P4C800/-E and/or Abit IC7/-G.
CPU External Frequency: 250MHz
DRAM Clock: Manually set to 1:1 or 400MHz
SDRAM CAS Latency: 3T
SDRAM RAS to CAS Delay (tRCD): 4T
SDRAM Row Precharge (tRP): 4T
SDRAM Active to Precharge Delay (tRAS): 8T
SDRAM Bank Interleave: 4 Bank
SDRAM VDIMM: 2.75
All other settings are motherboard defaults.
Maximum recommended VDIMM: 2.9



Testing parameters for TWINX4000:

TWINX1024-4000 Data Sheet
TWINX512-4000 Data Sheet
Motherboard make and model: Asus P4C800/-E and/or Abit IC7/-G.
Each pair is tested and packaged together using the following settings:
CPU External Frequency: Manually set to 250MHz
DRAM Clock: Manually set to 1:1 or 400MHz
SDRAM CAS Latency: 3T
SDRAM RAS to CAS Delay (tRCD): 4T
SDRAM Row Precharge (tRP): 4T
SDRAM Active to Precharge Delay (tRAS): 8T
SDRAM Bank Interleave: 4 Bank
SDRAM VDIMM: 2.75
All other settings are motherboard defaults.
Maximum recommended VDIMM: 2.9

Testing parameters for XMS4400:

CMX512-4400 Data Sheet
Motherboard make and model: Asus P4C800/-E
CPU External Frequency: Manually set to 275MHz
DRAM Clock: Manually set to 1:1 or 400MHz
SDRAM CAS Latency: 3T
SDRAM RAS to CAS Delay (tRCD): 4T
SDRAM Row Precharge (tRP): 4T
SDRAM Active to Precharge Delay (tRAS): 8T
SDRAM Bank Interleave: 4 Bank
SDRAM VDIMM: 2.75
All other settings are motherboard defaults.
Maximum recommended VDIMM: 2.9

Testing parameters for TWINX4400:

TWINX1024-4400 Data Sheet
Motherboard make and model: Asus P4C800/-E
Each pair is tested and packaged together using the following settings:
CPU External Frequency: Manually set to 275MHz
DRAM Clock: Manually set to 1:1 or 400MHz
SDRAM CAS Latency: 3T
SDRAM RAS to CAS Delay (tRCD): 4T
SDRAM Row Precharge (tRP): 4T
SDRAM Active to Precharge Delay (tRAS): 8T
SDRAM Bank Interleave: 4 Bank
SDRAM VDIMM: 2.75
All other settings are motherboard defaults.
Maximum recommended VDIMM: 2.9

Testing parameters for TWINX4400C25:

TWINX1024-4400C25 Data Sheet
Motherboard make and model: Asus P4C800/-E
Each pair is tested and packaged together using the following settings:
CPU External Frequency: Manually set to 275MHz
DRAM Clock: Manually set to 1:1 or 400MHz
SDRAM CAS Latency: 2.5T
SDRAM RAS to CAS Delay (tRCD): 4T
SDRAM Row Precharge (tRP): 4T
SDRAM Active to Precharge Delay (tRAS): 8T
SDRAM Bank Interleave: 4 Bank
SDRAM VDIMM: 2.75
All other settings are motherboard defaults.
Maximum recommended VDIMM: 2.9

XMS DDR2

Testing parameters for Twin2x1024-4300C3:
Twin2x1024-4300C3 Data Sheet
Motherboard make and model: ABIT AA8 Durramax and/or Asus P5AD2 Premium
Each pair is tested and packaged together using the following settings:
CPU External Frequency: Manually set to 200MHz
DDR2 SDRAM Clock: Manually set to 533MHz
DRAM Timing Selectable: Auto Yields the following timings
SDRAM CAS Latency: 3T
SDRAM RAS to CAS Delay (tRCD): 3T
SDRAM Row Precharge (tRP): 3T
SDRAM Active to Precharge Delay (tRAS): 8T
DDR2 SDRAM Voltage: 1.9
NB Voltage 1.9 Volts (On Abit AA8 Only)
All other settings are motherboard defaults.
Maximum DDR2 recommended VDIMM: 2.1 Volts

Testing parameters for Twinx/XMS2-5400C4:
CM2X256-5400C4 Data Sheet
CM2X512-5400C4 Data Sheet
TWIN2X1024-5400C4 Data Sheet
Motherboard make and model: ABIT AA8 Durramax and/or Asus P5AD2 Premium
Each pair is tested and packaged together using the following settings:
CPU External Frequency: Manually set to 250MHz
DDR2 SDRAM Clock: Manually set to 533MHz
DRAM Timing Selectable: Auto Yields the following timings
SDRAM CAS Latency: 4T
SDRAM RAS to CAS Delay (tRCD): 4T
SDRAM Row Precharge (tRP): 4T
SDRAM Active to Precharge Delay (tRAS): 12T
DDR2 SDRAM Voltage: 1.9
NB Voltage 1.9 Volts (On Abit AA8 Only)
All other settings are motherboard defaults.
Maximum DDR2 recommended VDIMM: 2.1 Volts

Testing parameters for Twinx/XMS2-5400UL:
Twin2x1024-5400UL Data Sheet
Testing parameters for CM2X512A-5400UL:
Twin2x1024-5400UL Data Sheet

Motherboard make and model: Asus P5AD2-E Premium
Each pair is tested and packaged together using the following settings:
AI Over Clock Tuner: Manual
CPU External Frequency: Manually set to 226MHz
DDR2 SDRAM Clock: Manually set to 678MHz
PCI Express Freq: Auto
PCI Freq: 33.33
Performance Mode: Standard
DRAM Timing Selectable: Manual
SDRAM CAS Latency: 3T
SDRAM RAS to CAS Delay (tRCD): 3T (Revised 6/27/2005)
SDRAM Row Precharge (tRP): 2T
SDRAM Active to Precharge Delay (tRAS): 8T
SDRAM Write Recovery Time: 4
DDR2 SDRAM Voltage: 2.1
Chipset Core Voltage: 1.7 Volts
All other settings are motherboard defaults.
Maximum DDR2 recommended VDIMM: 2.1 Volts

Testing parameters for Twinx/XMS2-6400C3:
Twin2x2048-6400C3 Data Sheet

Motherboard make and model: Asus P5WD2 or M2N32-SLI Premium/Deluxe
Each pair is tested and packaged together using the following settings:
AI Over Clock Tuner: Manual
CPU External Frequency: Manually set to 200MHz
DDR2 SDRAM Clock: Manually set to 800MHz
PCI Express Freq: Auto
PCI Freq: 33.33
Performance Mode: Standard
DRAM Timing Selectable: Manual
SDRAM CAS Latency: 3T
SDRAM RAS to CAS Delay (tRCD): 4T
SDRAM Row Precharge (tRP): 3T
SDRAM Active to Precharge Delay (tRAS): 9T
SDRAM Write Recovery Time: 5
DDR2 SDRAM Voltage: 1.9
CPU Core Voltage: Auto
FSB Termination V: 1.50 V
MCH Chipset V: 1.65V
ICH Chipset V: 1.20V
All other settings are motherboard defaults.
Maximum DDR2 recommended VDIMM: 2.1 Volts

Testing parameters for Twinx/XMS2-6400C4:
Twin2x2048-6400C4 Data Sheet

Motherboard make and model: Asus P5WD2 or M2N32-SLI Premium/Deluxe
Each pair is tested and packaged together using the following settings:
AI Over Clock Tuner: Manual
CPU External Frequency: Manually set to 200MHz
DDR2 SDRAM Clock: Manually set to 800MHz
PCI Express Freq: Auto
PCI Freq: 33.33
Performance Mode: Standard
DRAM Timing Selectable: Manual
SDRAM CAS Latency: 4T
SDRAM RAS to CAS Delay (tRCD): 4T
SDRAM Row Precharge (tRP): 4T
SDRAM Active to Precharge Delay (tRAS): 12T
SDRAM Write Recovery Time: 5
DDR2 SDRAM Voltage: 2.1
CPU Core Voltage: Auto
FSB Termination V: 1.50 V
MCH Chipset V: 1.65V
ICH Chipset V: 1.20V
All other settings are motherboard defaults.
Maximum DDR2 recommended VDIMM: 2.1 Volts


Testing parameters for Twinx/XMS2-6400:
Twin2x1024A-6400 Data Sheet
Twin2x2048-6400 Data Sheet

Motherboard make and model: Asus P5WD2 Premium/Deluxe
Each pair is tested and packaged together using the following settings:
AI Over Clock Tuner: Manual
CPU External Frequency: Manually set to 200MHz
DDR2 SDRAM Clock: Manually set to 800MHz
PCI Express Freq: Auto
PCI Freq: 33.33
Performance Mode: Standard
DRAM Timing Selectable: Manual
SDRAM CAS Latency: 5T
SDRAM RAS to CAS Delay (tRCD): 5T
SDRAM Row Precharge (tRP): 5T
SDRAM Active to Precharge Delay (tRAS): 15T
SDRAM Write Recovery Time: 5
DDR2 SDRAM Voltage: 1.9
Chipset Core Voltage: Auto
All other settings are motherboard defaults.
Maximum DDR2 recommended VDIMM: 2.1 Volts

Testing parameters for Twinx/XMS2-8000UL:
Twin2x1024-8000UL Data Sheet

Motherboard make and model: Asus P5WD2 Premium/Deluxe
Each pair is tested and packaged together using the following settings:
AI Over Clock Tuner: Manual
CPU External Frequency: Manually set to 250MHz
DDR2 SDRAM Clock: Manually set to 1000MHz
PCI Express Freq: Auto
PCI Freq: 33.33
CPU Core Voltage: Auto
FSB Termination V: 1.5 Volts
MCH Chiset V: 1.65 Volts
ICH Chiset V: 1.20 Volts
Performance Mode: Standard
DRAM Timing Selectable: Manual
SDRAM CAS Latency: 5T
SDRAM RAS to CAS Delay (tRCD): 4T
SDRAM Row Precharge (tRP): 4T
SDRAM Active to Precharge Delay (tRAS): 9T
SDRAM Write Recovery Time: 5
DDR2 SDRAM Voltage: 2.2
Chipset Core Voltage: Auto
All other settings are motherboard defaults.
Maximum DDR2 recommended VDIMM: 2.1 Volts, However this DDR2 module would be the only one rated at 2.2 Volts Max.

Testing parameters for Twinx/XMS2-8500/C5:
Twin2x1024-8500 Data Sheet
Twin2x2048-8500C5 Data Sheet

Motherboard make and model: Asus M2N32-SLI Premium/Deluxe
Each pair is tested and packaged together using the following settings:
AI Over Clock Tuner: Manual
OC Operation: Disabled
NOS Operation: Disabled
CPU External Frequency: Manually set to 268 MHz
PCI CLK1: Auto
PCI CLK2: Auto
DDR2 Voltage control: 2.200V
CPU Core Voltage: Auto
CPU Multiplier: 10
DDR2 SDRAM Clock: Manually set to 800MHz
DRAM Timing Selectable: Manual
SDRAM CAS Latency: 5T
SDRAM RAS to CAS Delay (tRCD): 5T
SDRAM Row Precharge (tRP): 5T
SDRAM Active to Precharge Delay (tRAS): 15T
SDRAM Write Recovery Time: 5
1T/2T: 2T
A1 Clock Skew: Auto
CKE: Auto
CS/ODT:1.00X
ADD/CMD:1.00X
MEMCLK:1.00X
DATA: Auto
DQS: Auto
DRAM: Auto
All other settings are motherboard defaults.
Maximum DDR2 recommended VDIMM: 2.2 Volts