Terrible slowdown on 4GB system, but super speedy with 2GB - 64bit OS. WTF!?

[Sunday Ironfoot]

OK, this is soo bizarre. So I bought an SSD (intel x26 160GB v2) and got a copy of Windows 7 x64. Installed everything and found the overal performance of the OS to be really slow and terrible. I even upgraded my CPU from 2.2GHz Core 2 (T7500) to a Penryn 2.6GHz (T9500), still terrible performance. I tried updating mobo BIOS, got all the latest updates and drivers. Still no joy.

I then put my old 7200RPM drive back in with Vista 32bit still on it, and the performance came back and it was fast and responsive. So I was thinking I had a defective SSD, or Windows 7 is actually really terrible and all the rave reviews were a conspiracy.

So on a whim, with the SSD + Win7x64 back in, I decided to remove one of my 2GB RAM sticks (I have 4GB). Suddenly the performance came back, no, it more than came back, I was blown away!! Boot time dropped from 1min 30 secs to about under 30 secs, more benchmarks below. It was like going from a G-Wiz to a Bugatti Veyron (no really).

So it seems the performance is diabolical with 4GB but simply amazing with 2GB. It's a laptop, and specs are below:

Intel Core 2 Duo 2.6GHz Penryn (T9500)
2GB or 4GB DDR2-677MHz RAM
Intel 965m Motherboard (latest BIOS)
Intel SSD x25 160GB (v2)
Windows 7 x64 RTM

And some benchmarks, bare in mind the only difference is 2GB vs 4GB:

System 1 (4GB RAM) | System 2 (2GB RAM)
Visual Studio 2008 large project compile time: 17 seconds | 3 seconds
Boot up Time: 1min 30sec | about 30 seconds
SSD 4K Random Read: 9MB | 20MB
SSD 4K Random Write: 11MB | 35MB

So it seems there is some weird compatibility issue when using 4GB RAM on my laptop with a 64bit OS. Using the full 4GB on my Vista 32bit OS doesn't cause any problems, although it only uses 3.15GB on Vista32. Has anyone ever had this problem before?

So I'm currently using the fastest, most responsive PC I've ever used (especially thanks to my SSD), but I would like my 2GB RAM back.

 

[Sunday Ironfoot]

And in case you think it's the memory, I placed each memory module in seperately. Both seem fine, still same excellent performance, it's only when both used together, and with 64bit OS, that I have problems.

 

[myocardia]

Have you considered that your motherboard chipset is too old to be trying to run 4GB of RAM, on Windows 7? That chipset is many generations old now, unfortunately. Which RAM did you add, BTW?

 

[glugglug]

You may want to check out this thread:
http://social.technet.microsof...4a43-819e-c58dd43ea054

Looks like a lot of people have this issue when using a Marvell NIC.

 

[Sunday Ironfoot]

Originally posted by: myocardia
Have you considered that your motherboard chipset is too old to be trying to run 4GB of RAM, on Windows 7? That chipset is many generations old now, unfortunately. Which RAM did you add, BTW?

Many generations old, are you kidding me! I was top of the line only two years ago, granted it's not nthe latest and gratest now, but it still works with a Penryn 45nm CPU which I believe is the latest/faster mobile CPU intel currently make. I'm pretty sure this motherboard is still being sold now.

And besides it's advertised as compatible with 4GB RAM. So it should work.

RAM is 2x 2GB DDR2 677MHz Kingston, now running just 1x 2GB stick.

 

[Sunday Ironfoot]

Originally posted by: glugglug
You may want to check out this thread:
http://social.technet.microsof...4a43-819e-c58dd43ea054

Looks like a lot of people have this issue when using a Marvell NIC.

I'm not using a Marvel NIC, it's a built in intel Gigabit network card, and built in intel wireless adaptor, but thanks for the link.

 

[Sunday Ironfoot]

I have a hunch it could be a memory mapping issue with other devices (eg. graphics card) own memory not being correctly mapped outside the 4GB range.

On 32bit OS's you don't get the full 4GB because your graphic card probably has 512MB which needs to get mapped within that 4GB range limit, so you end up with something like 3.5GB, or 3.15GB in Vista. With a 64bit OS however, modern motherboards remap that range set aside for other devices to outside the maximum memory the motherboard supports, so you can use the full 4GB or 8GB or whatever your mobo supports.

So it could be my motherboard isn't correctly remapping this outside the 4GB limit. Problem is how do I fix this? Might need to contact ASUS or Intel.

What do you people think?

 

[Yellowbeard]

What specific model of notebook are you running? And, do you have a link to it or to the MOBO spex?

I'm thinking this is going to be chipset related as Myocardia pointed out.

 

[Sunday Ironfoot]

Originally posted by: Yellowbeard
What specific model of notebook are you running? And, do you have a link to it or to the MOBO spex?

I'm thinking this is going to be chipset related as Myocardia pointed out.

It's an ASUS Lamborghini VX2S http://usa.asus.com/products.a...model=1782&modelmenu=2

Mobo is intel PM965 Express Chipset Santa Rosa (the first chipset where intel introduced the flash cache chip), Southbridge is ICH8-M. http://www.intel.com/cd/produc...ng/chipsets/345162.htm

 

[RebateMonger]

For what it's worth.....

I have a FoxConn 965-based motherboard that has 8 GB of memory (4x2 GB) and runs just fine with XP (32-bit) and Server 2008 (64-bit). Assuming the BIOS isn't badly done, the 965 itself can definitely work with "large" amounts of memory.

 

[Sunday Ironfoot]

Interesting update. I tried swapping RAM between the two memory slots. I seem to have intemittent problems with slot 2, but slot 1 is fine, with either memory module. It's interesting, I tried slot 2 and it took ages to boot up, but once booted, it was responably fast, so I rebooted but it wouldn't start up at all, no POST screen. So I took the RAM out of slot 2 and put back in slot 1 and everything is fine again, fast 20 sec bootup etc.

Faulty memory slot? With both memory sticks in I just get slow performance, it doesn't ever crash, and seems to boot up fine, albeit really slowly.

 

[Sunday Ironfoot]

OK, final update. I put a 1GB stick in the memory slot that is supposedly faulty to make 3GB, working perfectly! I suppose that'll have to do. The saga ends. Please just let this thread die.

On a related note, I can't recommend Intel's x25 SSD enough, getting 20 second boot up time here (30 including POST screen)!