[resolved]1 GB + 256MB DDR Dual Channel RAM Problem

Gemo · 04-03-2007, 04:23 PM

On my Asus P5GD1 m/b I have two 256 DDR-400's installed for a total of 512 MB RAM.

Today I picked up two new 1GB DDR chips and tried to install them. I put the 1GB's in the blue (primary???) RAM slots and the 256 MB's in the black (secondary???) mem slots - but my PC wouldn't boot, and in fact it wouldn't get through the BIOS (ie no beep). (- and afterwards I need to refresh the BIOS)

When I only install the two new 1GB mems the PC works fine and WinXP shows 2 GB of RAM. When I just install the two old 256 MBs the PC boots OK and shows 512MB of mem.

What's going on here? Can't imagine why these 2 different memory sizes won't work together...

1 g0t 0wn3d · 04-03-2007, 04:48 PM

maybe your mobo only supports 2 gb ram

alabamaman79 · 04-03-2007, 05:11 PM

That's odd, your board should default back to single-channel mode at the very least, if it doesn't support dual-channel mode with differing sizes in the banks. Try resetting your CMOS:

Unplug the power cable from the back of your PC. Open up your computer and find your CMOS battery (looks like a large watch battery) and remove it from its holder. Install all 4 RAM sticks into your DIMM slots, put the 1GB sticks in the first bank (DIMM 0 and 1) and the 256MB sticks in the second bank (DIMM 2 and 3). Let the PC sit for 5 minutes without the CMOS battery in its holder, this will reset your CMOS. After 5 minutes, put the battery back into the board, close up your PC and plug the power cable back in and fire it up. Let us know the results.

Also, if for some odd reason you can't get all 4 sticks working at the same time, 2GB is a very nice amount of RAM, and there's not much difference between 2GB and 2.5GB.

**mattlock** · 04-04-2007, 01:31 AM

You probably need to increase your Vdimm in the bios. That's the only way may Asus A8n Sli would boot with 4 sticks of ram. I increased 2.6v to 2.7 and it's worked every since without a hitch.

Gemo · 04-04-2007, 09:16 AM

Many thanks for the comments - very helpful.

I'll try some of these ideas but last night I thought I would try using the two 256MB's in another computer.

So I installed them in my kid's PC (which interestingly also uses an Asus P5GD1 m/b!). This PC was already using two 512MBs so I inserted the 256MBs beside the 512MBs and lo and behold when the PC rebooted I had 1.5GB of RAM.

So at least for the time being - considering I have my machine with 2GB and the kids unit with 1.5GB this is probably the best use of the 'spare' 256MBs.

**mattlock** · 04-04-2007, 09:47 AM

Quote:

Originally Posted by Gemo

Many thanks for the comments - very helpful.

I'll try some of these ideas but last night I thought I would try using the two 256MB's in another computer.

So I installed them in my kid's PC (which interestingly also uses an Asus P5GD1 m/b!). This PC was already using two 512MBs so I inserted the 256MBs beside the 512MBs and lo and behold when the PC rebooted I had 1.5GB of RAM.

So at least for the time being - considering I have my machine with 2GB and the kids unit with 1.5GB this is probably the best use of the 'spare' 256MBs.

Great to hear. Problem solved and everybody is happy.

04-03-2007, 04:23 PM	#1 (permalink)
Gemo Registered User Join Date: Aug 2004 Posts: 48 OS: Win98	[resolved]1 GB + 256MB DDR Dual Channel RAM Problem On my Asus P5GD1 m/b I have two 256 DDR-400's installed for a total of 512 MB RAM. Today I picked up two new 1GB DDR chips and tried to install them. I put the 1GB's in the blue (primary???) RAM slots and the 256 MB's in the black (secondary???) mem slots - but my PC wouldn't boot, and in fact it wouldn't get through the BIOS (ie no beep). (- and afterwards I need to refresh the BIOS) When I only install the two new 1GB mems the PC works fine and WinXP shows 2 GB of RAM. When I just install the two old 256 MBs the PC boots OK and shows 512MB of mem. What's going on here? Can't imagine why these 2 different memory sizes won't work together...

04-03-2007, 04:48 PM	#2 (permalink)
1 g0t 0wn3d Hardware Team Join Date: Jan 2007 Location: Sedona, az Posts: 6,274 OS: Vista basic 32bit My System	Re: 1 GB + 256MB DDR Dual Channel RAM Problem maybe your mobo only supports 2 gb ram __________________ Bench Test \| PC Wizard \| System specs \| PSU info \| PSU calculator \| Memtest86+ \| Speedfan

04-03-2007, 05:11 PM	#3 (permalink)
alabamaman79 Registered User Join Date: Mar 2007 Posts: 169 OS: WinXP My System	Re: 1 GB + 256MB DDR Dual Channel RAM Problem That's odd, your board should default back to single-channel mode at the very least, if it doesn't support dual-channel mode with differing sizes in the banks. Try resetting your CMOS: Unplug the power cable from the back of your PC. Open up your computer and find your CMOS battery (looks like a large watch battery) and remove it from its holder. Install all 4 RAM sticks into your DIMM slots, put the 1GB sticks in the first bank (DIMM 0 and 1) and the 256MB sticks in the second bank (DIMM 2 and 3). Let the PC sit for 5 minutes without the CMOS battery in its holder, this will reset your CMOS. After 5 minutes, put the battery back into the board, close up your PC and plug the power cable back in and fire it up. Let us know the results. Also, if for some odd reason you can't get all 4 sticks working at the same time, 2GB is a very nice amount of RAM, and there's not much difference between 2GB and 2.5GB.

04-04-2007, 01:31 AM	#4 (permalink)
mattlock moderator hardware team Join Date: Dec 2005 Location: Ohio Posts: 3,818 OS: XP SP2, Ubuntu Gutsy Gibbon My System	Re: 1 GB + 256MB DDR Dual Channel RAM Problem You probably need to increase your Vdimm in the bios. That's the only way may Asus A8n Sli would boot with 4 sticks of ram. I increased 2.6v to 2.7 and it's worked every since without a hitch. __________________ Matt Everest-Thermal Paste Instruction-Power Supply Info-Sensorview PSU Calculator-Speedfan-Bench Test Help TSF Fight Disease. It's Free!

04-04-2007, 09:16 AM	#5 (permalink)
Gemo Registered User Join Date: Aug 2004 Posts: 48 OS: Win98	Re: 1 GB + 256MB DDR Dual Channel RAM Problem Many thanks for the comments - very helpful. I'll try some of these ideas but last night I thought I would try using the two 256MB's in another computer. So I installed them in my kid's PC (which interestingly also uses an Asus P5GD1 m/b!). This PC was already using two 512MBs so I inserted the 256MBs beside the 512MBs and lo and behold when the PC rebooted I had 1.5GB of RAM. So at least for the time being - considering I have my machine with 2GB and the kids unit with 1.5GB this is probably the best use of the 'spare' 256MBs.