I purchased some components to put a PC together and it seems I have
screwed up. I bought the PC4800-E Deluxe board plus 2 sticks of
Corsair CMX512R-3200C2 DDR. This RAM is registered memory. Upon boot
up I get a constant cycle of 3 beeps, which is a failure to read/write
main memory. Am I correct in believing that this board does not
support registered memory?
Thank You
You can get the manual here:
ftp://ftp.asus.com.tw/pub/ASUS/mb/sock478/P4C800E-DX/e1347b_p4c800-e_deluxe.pdf
It only mentions "unbuffered" memory, either with ECC or without. With
Asus, that doesn't mean that it uses ECC, just that it won't blow up if
you use ECC memory. The fact that registered is not supported can be
verified here, in the Intel 875 Northbridge spec:
http://developer.intel.com/design/chipsets/datashts/25252501.pdf (2.6MB)
"Registered DIMMs not supported (Pg.18)"
The Northbridge datasheet does mention ECC support, so you would have to
check the BIOS to see whether a magic ECC option appears when an ECC
module is plugged in. Some Asus motherboards have an ECC item added to
a BIOS screen, once an ECC DIMM is used.
So, I would return the registered modules for some unbuffered ones.
Whether you buy an ECC module or not depends on whether this is a
home system or an (ultra-reliable) business system. ECC can cause a
slowdown in memory bandwidth, when a read-modify-write cycle is needed
to update a single byte in a 72 bit wide memory access to the DIMM.
For a home system, just buy unbuffered non-ECC memory.
HTH,
Paul
