I'm a little out of date when it comes to memory but my understanding is this should work and it isnt. Bought a brand new ASUS P5K-E motherboard with 2 sticks of Crucial PC2-6400 memory and if i put both sticks in DIMM1 and 2 (respectively) system POSTS and everything is fine but the POST states (and cpu-z confirms) that my RAM Is in single channel. which makes sense because i think 1 and 2 are both in the same bank. If i move one of them over to a different slot, the system wont POST. i dont get any error beeps (i dont know if i should with the P5K-E, i'm new to this motherboard), but i dont get video or keyboard lights or anything, just fans turning. If i put the two sticks of ram back in the original slots, everything is fine. It was my understanding (limited as it is) that putting one stick in one bank and one stick in the other bank would allow for me to do dual channel memory. the memory should support it and i bought it as a 2 gig kit (two 1gb sticks in a package).

Any ideas what i'm doing wrong here?

Here is a dump from CPU-Z of what i figure is the relevant stuff:

-------------------------
CPU-Z version 1.44
-------------------------

Processors Map
------------------------------------------------------------------------------------

Number of processors 1
Number of threads 2

Processor 0
-- Core 0
-- Thread 0
-- Core 1
-- Thread 0


Processors Information
------------------------------------------------------------------------------------

Processor 1 (ID = 0)
Number of cores 2 (max 2)
Number of threads 2 (max 2)
Name Intel Core 2 Duo E8400
Codename Wolfdale
Specification Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz
Package Socket 775 LGA (platform ID = 0h)
CPUID 6.7.6
Extended CPUID 6.17
Core Stepping C0
Technology 45 nm
Core Speed 2003.9 MHz (6.0 x 334.0 MHz)
Rated Bus speed 1335.9 MHz
Stock frequency 3000 MHz
Instructions sets MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, EM64T
L1 Data cache 2 x 32 KBytes, 8-way set associative, 64-byte line size
L1 Instruction cache 2 x 32 KBytes, 8-way set associative, 64-byte line size
L2 cache 6144 KBytes, 24-way set associative, 64-byte line size
FID/VID Control yes
FID range 6.0x - 9.0x
max VID 1.225 V
Features XD, VT


Chipset
------------------------------------------------------------------------------

Northbridge Intel P35/G33/G31 rev. A2
Southbridge Intel 82801IR (ICH9R) rev. 02
Graphic Interface PCI-Express
PCI-E Link Width x16
PCI-E Max Link Width x16
Memory Type DDR2
Memory Size 2048 MBytes
Channels Single
Memory Frequency 400.8 MHz (5:6)
CAS# 5.0
RAS# to CAS# 5
RAS# Precharge 5
Cycle Time (tRAS) 18
Command Rate 2T


Memory SPD
------------------------------------------------------------------------------

DIMM #1

General
Memory type DDR2
Module format Regular UDIMM
Manufacturer (ID) Crucial Technology (7F7F7F7F7F9BFFFF)
Size 1024 MBytes
Max bandwidth PC2-6400 (400 MHz)
Part number
Serial number 8305CC29

Attributes
Number of banks 1
Data width 64 bits
Correction None
Nominal Voltage 1.80 Volts
EPP yes (2 profiles)
XMP no

Timings table
Frequency (MHz) 333 400
CAS# 4.0 5.0
RAS# to CAS# delay 5 5
RAS# Precharge 5 5
TRAS 15 18
TRC 20 23

EPP profile 1 (full)
Voltage level 2.200 Volts
Address Command Rate 2T
Cycle time 2.500 ns (400.0 MHz)
tCL 4.0 clocks
tRCD 4 clocks (10.00 ns)
tRP 4 clocks (10.00 ns)
tRAS 12 clocks (30.00 ns)
tRC 24 clocks (60.00 ns)
tWR 6 clocks (15.00 ns)

EPP profile 2 (full)
Voltage level 2.200 Volts
Address Command Rate 2T
Cycle time 2.000 ns (500.0 MHz)
tCL 5.0 clocks
tRCD 5 clocks (10.00 ns)
tRP 5 clocks (10.00 ns)
tRAS 15 clocks (30.00 ns)
tRC 30 clocks (60.00 ns)
tWR 8 clocks (15.00 ns)


DIMM #2

General
Memory type DDR2
Module format Regular UDIMM
Manufacturer (ID) Crucial Technology (7F7F7F7F7F9BFFFF)
Size 1024 MBytes
Max bandwidth PC2-6400 (400 MHz)
Part number
Serial number 8305CC53

Attributes
Number of banks 1
Data width 64 bits
Correction None
Nominal Voltage 1.80 Volts
EPP yes (2 profiles)
XMP no

Timings table
Frequency (MHz) 333 400
CAS# 4.0 5.0
RAS# to CAS# delay 5 5
RAS# Precharge 5 5
TRAS 15 18
TRC 20 23

EPP profile 1 (full)
Voltage level 2.200 Volts
Address Command Rate 2T
Cycle time 2.500 ns (400.0 MHz)
tCL 4.0 clocks
tRCD 4 clocks (10.00 ns)
tRP 4 clocks (10.00 ns)
tRAS 12 clocks (30.00 ns)
tRC 24 clocks (60.00 ns)
tWR 6 clocks (15.00 ns)

EPP profile 2 (full)
Voltage level 2.200 Volts
Address Command Rate 2T
Cycle time 2.000 ns (500.0 MHz)
tCL 5.0 clocks
tRCD 5 clocks (10.00 ns)
tRP 5 clocks (10.00 ns)
tRAS 15 clocks (30.00 ns)
tRC 30 clocks (60.00 ns)
tWR 8 clocks (15.00 ns)

My cpu-z also shows channels# single...

DDR2 should show dual channel, right?...

DDR2 might not show dual channel by default as OP suggests RAM has to be in the correct slots on the board (refer to manual on this) and then it may still have to be enabled in the BIOS

OP... have you tried resetting the CMOS or trying the other 2 RAM slots for dual channel?

Not all DDR2 comes in single and dual channel. Check yours to make sure it is dual channel.

I'm having the exact same problem with my P5K-E/WiFi-AP. I've tried Crucial, Corsair, OCZ, Kingston ram, I've settled with Crucial Ballistix DDR2 800 dual channel kit (Model # BL2KIT12864AA804) in the end. System would only post when I have the memory sticks inserted in bank 1 and 2 (yellow and black), which forces my dual channel memory to work only in single channel mode. Installing only 1 Gb of ram in bank 1 also allows the system to post but any combination other than Bank 1/Bank 1+ 2 and the system won't post, all the lights and fans come on but I get no signal. I've tried searching in the Asus support forum but apparently it's filled with customer complaints in most threads with no real interaction or solution offered by the company.

Anyways I'm thinking it's a bad memory slot cuz I just got another dual channel kit today of the exact same model as the one I have. (Crucial Ballistix Model # BL2KIT12864AA804) With 1 kit in bank 1 + 2, I installed the other two sticks in bank 3 + 4, once again no post, Bank 1 + 2 + 3, no post. Figures.

Ok a little more searching online and I bumped into this thread...

http://forum.ncix.com/forums/index [...] rclockid=0

So...lesson learned, guess there is no workaround except to do with single channel or get a new mobo. Thanks Asus!