• Notice regarding image hosts and attachments. See here.

Dual Channel question

GreatWaves

GreatWaves

GreatWaves

Associate
Joined
9 Dec 2008
Posts
387
I got two 512MB DDR1 PC4000 A-Data sticks for this system: Abit NF7-S v2, Athlon XP-M 2500+ (outdated I know... can explain later).

The extended BIOS mem check during boot says they are "OK" and CPUID reports 1 Gig of dual channel RAM. Everything seems to check out.

But when I run Prime95 "blend test" (which tests lots of RAM), the system starts caching like crazy and CPU load never gets above 10% or so. I can see from the task manager that most of the RAM gets allocated during the Prime95 run.

What's going on? My own guess is that these two sticks cannot run as Dual Channel. If so, do I just move the 2nd stick over to the slot right next to the first stick (into the same bank)?

By the way, the reason I'm running DDR500 with this CPU is because they are the only 512MB DDR's that I have. I need 1 Gig onboard because the GFX card that's going in requires that. Otherwise I would put in my 256MB DDR466 sticks.

Thanks
 
Erm I don't think Prime95 is designed to run on components that old.

And why in hell are you using a components that old??? AND trying to overclock them???

Are you ok???
 
Isn't your main problem just a lack of RAM?

1GB isn't much and by the time you've loaded Windows etc. I doubt there's much left for anything else.

You'd be in an even worse predicament running with 512MB (if you have 2x256MB sticks).

What graphics card are you getting?

The motherboard has an AGP slot for graphics cards and virtually every graphics card sold now needs a PCI-E slot.
 
Surveyor said:
Isn't your main problem just a lack of RAM?

1GB isn't much and by the time you've loaded Windows etc. I doubt there's much left for anything else.

You'd be in an even worse predicament running with 512MB (if you have 2x256MB sticks).

What graphics card are you getting?

The motherboard has an AGP slot for graphics cards and virtually every graphics card sold now needs a PCI-E slot.
Click to expand...
Talking WinXP Pro here, not Win7... WinXP runs totally fine on 512 MB. 2x256MB was what it had before I put in these 2x512MB sticks.

Oh and the GFX card I referred to is AGP (HD 4650, 1Gig DDR2, 128 bit)
 
CinderzFTW said:
Erm I don't think Prime95 is designed to run on components that old.

And why in hell are you using a components that old??? AND trying to overclock them???

Are you ok???
Click to expand...
This is the same copy of Prime95 that I've used many dozens of times on these mobos, cpu's before.

I've OC's these components years ago.... I've setting them up again for crunching just for fun.
 
I assume the purpose of buying a HD 4650 is for gaming?

HD 4650, 1GB RAM and Athlon XP-M 2500+.

I hope you either don't have high expectations or you'll be playing very undemanding games at pretty low resolution.
 
So anyway... the overall suitability of the hardware and OS is OK. I know because I used these components before.

That out of the way... what could be causing the system to cache like crazy during Prime95 "blend test"? Again, MemTest86 v4.2 just told me that the RAM checks out.

Should I try the RAM in non-dual channel mode? Do I simply move stick #2 over next to the first stick?

Thanks
 
Surveyor said:
I assume the purpose of buying a HD 4650 is for gaming?

HD 4650, 1GB RAM and Athlon XP-M 2500+.

I hope you either don't have high expectations or you'll be playing very undemanding games at pretty low resolution.
Click to expand...
No high end gaming... just a couple of RC sims that I know run on these components with 512MB RAM and even more modest GFX card.
 
Just wanna reset this thread again. This is old hardware, but it will be running old OS/software that I know it can handle.

Back to Dual Channel... can the sticks not being similar enough to each other (they ARE same brand and model tho) and therefore not suitable for dual channel cause excessive caching in some cases? I've read that it can cause system instability... not sure what kind.

Thanks
 
An update: I just noticed that when Prime95 "blend test" starts it first allocates most of the physical RAM (as I think it should) but THEN it starts allocating most of the virtual memory as well .... As it is then attempting to operate with HDD memory as though it were physical RAM, it obviously runs slowly.

This is wierd. It did not do that when I had the 2x256MB sticks installed. It's never done this until I put in these new A-Data PC4000 2x512MB sticks. (NF7-S v2 can handle PC4000 by the way).

Why would Prime95 think that the system's physical memory is RAM+Virtual Memory?
 
Could someone tell me if disabling Dual Channel involves just moving stick#2 over next to stick#1 (to the same bank) and nothing else needs to be set?

Thanks :)
 
GreatWaves said:
Could someone tell me if disabling Dual Channel involves just moving stick#2 over next to stick#1 (to the same bank) and nothing else needs to be set?

Thanks :)
Click to expand...

Yes, that should do it but why? In my opinion I agree with what others have said above, that is your RAM is too low for the latest versions of Prime95. Caching is the direct result of your OS using a swapfile to simulate the lack of sufficient RAM, dual channel meanwhile is the process of enabling reading/writing to to memory banks concurrently.
 
EggCustard said:
Yes, that should do it but why? In my opinion I agree with what others have said above, that is your RAM is too low for the latest versions of Prime95. Caching is the direct result of your OS using a swapfile to simulate the lack of sufficient RAM, dual channel meanwhile is the process of enabling reading/writing to to memory banks concurrently.
Click to expand...
Thanks for answering my question :) I guess that changing to not dual channel can be a good option in some cases.

About the amount of RAM, OS and Prime95: I guess people are not used to seeing any discussion these days about this hardware (Athlon XP/Intel P4). The Prime95 is the same version/copy of Prime95 that I've run on this hardware many times and with even less RAM. I've run it on a Win2K machine with only 256MB RAM. I've run it on WinXP with only 512MB RAM. So 1024MB (on WinXP) is not too little for it. And WinXP can and does run totally fine on only 512MB (I guess no one here has installed that little RAM before).

Prime95 itself (or at least the version I'm using) needs a tiny amount of memory for itself and then it allocates the physical memory that's available for RAM testing purposes (if running "blend test").

So with the above established, I'm still wondering what could lead to it behaving this way (allocating RAM+Virtual Memory) after I upgraded RAM from 512MB (2x256, dual channel) to 1024MB (2x512, dual channel). Prime95 behaved normally when this system had only 512MB dual channel RAM.

Again, I used MemTest86 v4.2 to test these RAM sticks. They passed MemTest with zero errors.

Cheers :)
 
Last edited:
Just wanted to see if anyone happened to know off the top of their head of other instances where an app for some reason mistakes RAM+Virtual Memory for the system's total RAM.

Doesn't matter because I can use the "Custom" option in Prime95 that lets you choose how much Prime95 allocates for testing. If I set it manually to allocate 500MB it works fine. When using Custom mode you just have to remember to lower the maximum FFT size to around the maximum that "blend test" uses. The default maximum is much larger than in "blend test" and probably too heat inducing for a continuous test.

Anyway there is probably something quirky between my NF7 mobo and the specific RAM I have installed. I'lll try some different RAM sticks.

Cheers
 
Prime95 is one thing but other applications in the background including those in the tasy tray area when Windows loads all consume physical memory too. My assumption therefore is that you have a system with 1GB in total, however once Windows is all up and loaded, your free physical memory is way below 1GB, likely around 750MB and as such Prime95 when run on Large FFT will exceed the amount of memory that's free. Once this happens the spill over effect happens as noted earlier, where your hard drive is hard at work stimulating read and write ops to its swapfile.

You may also try running custom runs in Prime95 by restricting the sample size to see how this affects matters.
 
EggCustard said:
Prime95 is one thing but other applications in the background including those in the tasy tray area when Windows loads all consume physical memory too. My assumption therefore is that you have a system with 1GB in total, however once Windows is all up and loaded, your free physical memory is way below 1GB, likely around 750MB and as such Prime95 when run on Large FFT will exceed the amount of memory that's free. Once this happens the spill over effect happens as noted earlier, where your hard drive is hard at work stimulating read and write ops to its swapfile.

You may also try running custom runs in Prime95 by restricting the sample size to see how this affects matters.
Click to expand...
I appreciate everyone's replies, so don't take this as complaining, but I have to keep reminding that I know empirically that Prime95 is not supposed to behave that way. I have dozens of times run "blend test" on WinXP with 512MB RAM and on Win2K with 256MB RAM. It's not supposed to allocate a fixed amount regardless of what the physical RAM is. It allocates the amount of physical RAM that's available and runs the test with that.

So something weird starts going on on this particular computer when it has 1GB RAM. Like I've mentioned, it did NOT do the over-allocation on this same computer when it still had 512MB RAM (2x256).

Cheers
 
CinderzFTW said:
Erm I don't think Prime95 is designed to run on components that old.
Click to expand...

lol? So i must've dreamt prime95 back when i used to test K6/2/3 and Pentium cpus, when they were NEW? :D Its been around a long time mate. Also pretty sure i ran a reasonably new (latest at the time) build of it last yr on a mates firewall K6-3+ box under win2k.

As to the OP, i suppose the DC could be causing issues, have you tried running a single 512 and checking? Maybe downlock the timings and or give it say 2.8v. I guess a lot of folks don't remember when XP first came out that 256mb was a fair bit of memory, i think the first time i used an NF-7 board i had a 2700+ (VERY expensive at the time!) and 512mb Corsair memory which cost quite a pretty penny as well :)
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom