Mixing Kingston KVR400X64C3 with KVR400X64C3A possible?

[Norman]

I currently have the Asus P4P800-Deluxe and two Kingston
KVR400X64C3/256 installed (512MB total) running in dual-channel mode.
I want to bump up the ram to 1GB by adding another 2 pieces of 256MB.
After some searching, I notice that most of the store only carries
KVR400X64C3A/256 and not KVR400X64C3/256. And for those store that do
carry the KVR400X64C3/256, there's a price difference of at least $10
higher compare to the KVR400X64C3A/256.

I've heard this motherboard is very picky when it comes to using 4
sticks of ram. What's the difference between KVR400X64C3/256 and
KVR400X64C3A/256? Can I mix two sticks of KVR400X64C3/256 with two
sticks of KVR400X64C3A/256 and still be running in dual-channel mode?

 

[Paul]

I currently have the Asus P4P800-Deluxe and two Kingston
KVR400X64C3/256 installed (512MB total) running in dual-channel mode.
I want to bump up the ram to 1GB by adding another 2 pieces of 256MB.
After some searching, I notice that most of the store only carries
KVR400X64C3A/256 and not KVR400X64C3/256. And for those store that do
carry the KVR400X64C3/256, there's a price difference of at least $10
higher compare to the KVR400X64C3A/256.

I've heard this motherboard is very picky when it comes to using 4
sticks of ram. What's the difference between KVR400X64C3/256 and
KVR400X64C3A/256? Can I mix two sticks of KVR400X64C3/256 with two
sticks of KVR400X64C3A/256 and still be running in dual-channel mode?

http://www.valueram.com/Tools/Datasheets.asp

http://www.valueram.com/datasheets/KVR400X64C3_256.pdf
http://www.valueram.com/datasheets/KVR400X64C3A_256.pdf

C3A has slightly faster Trc. Clock period 5 to 10ns, means it
runs from DDR200 to DDR400. By default your motherboard applies
at least 2.6V, so no problems there. C3A appears to run cooler
as well - less watts of power.

From an end user perspective, no significant difference I can see.
Unless it is known in some overclocking group, that the chips
on one module are better overclockers than the other, I don't
see a $10 difference.

As usual, match the pairs across the channels properly. A1=B1 and
A2=B2, as per the manual.

HTH,
Paul

 

[Navid]

http://www.valueram.com/Tools/Datasheets.asp

http://www.valueram.com/datasheets/KVR400X64C3_256.pdf
http://www.valueram.com/datasheets/KVR400X64C3A_256.pdf

C3A has slightly faster Trc. Clock period 5 to 10ns, means it
runs from DDR200 to DDR400. By default your motherboard applies
at least 2.6V, so no problems there. C3A appears to run cooler
as well - less watts of power.

From an end user perspective, no significant difference I can see.
Unless it is known in some overclocking group, that the chips
on one module are better overclockers than the other, I don't
see a $10 difference.

As usual, match the pairs across the channels properly. A1=B1 and
A2=B2, as per the manual.

HTH,
Paul

Paul,

According to ASUS, the motherboard does not support 4 modules of this memory
inserted into both blue and black slots.
http://usa.asus.com/products/mb/socket478/p4p800-d/P4P800_DDR400_QVL.pdf

Navid

 

[Paul]

Paul,

According to ASUS, the motherboard does not support 4 modules of this memory
inserted into both blue and black slots.
http://usa.asus.com/products/mb/socket478/p4p800-d/P4P800_DDR400_QVL.pdf

Navid

A fair enough comment. What do you make of the fact that a Hynix
single sided module with D43 ram on it works in four slots, and
a Kingston single sided module with Hynix D43 chips on it doesn't
work in four slots. Does that build your faith in Asus ability to
test ?

256MB Hynix HYMD232646B8J-D43 AA Hynix SS HY5DU56822BT-D43 V V V
256MB Kingston KVR400X64C3A/256 hynix SS HY5DU56822BT-D43 V V -

You can also compare two double sided modules with hynix to
four single sided modules, and again the results aren't consistent,
although the number of memory chips involved is the same.

As a tie breaker, th OP could phone up Kingston and see if the ram
is made with more than one kind of chips. Perhaps they have a version
of C3A they ship to owners of P4P800/P4P800_Deluxe ? They might know
if there is an issue with Hynix chips and not with some other.
(Valueram uses more than one kind of memory chip.)

Asus doesn't document their test method or their sample size. I would
place more weight on their results, if I knew how they got them. If
the results said "2 of 76 modules tested failed", then we would know
how large a sample size they used.

Diff between C3 and C3A - 3-4-4 versus 3-3-3 timing.
http://www.abxzone.com/forums/showthread.php?t=52486

Memory tested by Intel on D865PERL - C3/C3A listed:
http://www.intel.com/design/motherbd/rl/rl_internalmem.htm

HTH,
Paul