MSI P6N SLI Platinum

[reaverblade]

i have an MSI P6N SLI platinum and TWIN2X2048-6400C4 (2x1GB)

 

i also have 2 sets of value-select:

VS2GBKIT533D2 (2x1GB)

VS1GBKIT533D2 (2x512MB)

 

which ones of the last 2 can i use with the first set? i want to maximize the memory as much as possible

 

thanks

[RAM GUY]

Neither set would be suggested. You would need to match what you have now in part number and revision for best performance and with 4 modules you will have to run the memory at DDR667.

[reaverblade]

...and with 4 modules you will have to run the memory at DDR667.

 

but doesn't the TWIN2X2048-6400C4 run at 800MHZ? not 667MHZ?

[RAM GUY]

Yes but with 4 Modules DDR667 would be suggested.

[DerekT]

but doesn't the TWIN2X2048-6400C4 run at 800MHZ? not 667MHZ?

The on motherboard memory controller (MCH - Northbridge) can not keep up with the extra DRAM at the rated 6400 speed. You will need to drop the speed of the DRAM from 800Mhz to 667Mhz. If you had purchased 4 X 1024MB of PC8500 (1066Mhz) DRAM, then you would have had to drop to PC6400 (800MHz) DRAM, etc. 2 X 2048 will not issue this problem. This is a problem of all 4 banks being populated.

 

Think of it this way. If you have a small phone book, then when you go into the index to find the page where you will find the phone number you are doing so at a certain speed due to the pages of the Index. Then you have to drive through the pages to get to the number. Now if your index is twice as large and the pages twice as many, then it takes longer to access the data. Now DRAM has a Strobe and the length of the strobe is how long the rows and columns can be left open before they must be refreshed. There is not enough time for the dram to be refreshed and then accessed with 4GB at the full access speed of the DRAM. The chipsets are optimized for 2GB, not 4GB and for 2 DRAM slots, not 4 DRAM slots populated. You can overclock the FSB (and hence the Memory Controller Hub = MCH) to gain some extra bandwidth and thus access the capabilities of the DRAM since the chipset is now clocked up. Usually when you clock up the FSB and concurrently the Memory Controller Hub (MCH) you need to raise the voltages of the CPU/MCH a bit as well.

[reaverblade]

if i do run it at a higher mhz...what are the consequences?

 

would the computer crash? would it have trouble switching on?

 

(im asking because my old computer had both sets of the afore said valueselect rams and i had trouble powering on the computer....at first i thought it was a power supply problem, but after i learned about this lowering of mhz...i am concerned its a memory problem

[RAM GUY]

Its hard to say exactly what might happen but it would not be stable if the settings are too aggressive for the configuration you have. Just try it and test the system with http://www.memtest.org to be sure its satble.

[DerekT]

if i do run it at a higher mhz...what are the consequences?

 

would the computer crash? would it have trouble switching on?

 

(im asking because my old computer had both sets of the afore said valueselect rams and i had trouble powering on the computer....at first i thought it was a power supply problem, but after i learned about this lowering of mhz...i am concerned its a memory problem

 

For total system stability and longevity, you would do well to keep the system at defaults and the DRAM at 667 to make use of the four DRAM banks being populated.

 

I would have to know what your old system was before rendering a view on the powering off issue. Certainly A8n-SLi Deluxe boards had this issue with 4 Banks being populated. There are others as well.