PC runs V E R Y S L O W after coming out of retirement

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BW

I got out an old PC from broom closet.It has Gigabyte 965P mainboard,
Core 2 2666 and DDR2 667 RAM.
Now it is amazingly slow. I have a home-theatre PC also with 965
chipset, but only an 1866 MHz CPU and
that goes about 10 times as fast.
Everthing seems slow, from disk access to drawing graphics. Booting
and shutting down takes aeons.
It has linux installed. I checked "top" command and there are no
phantom processes using up all the CPU cycles.
And there is free RAM, it is not using swap disk.
I checked BIOS settings, and everything is optimum without
overclocking. I know if you do something like
turn off L2 cache, that is worth roughly 10% penalty not 10x.
I ran memest program and it shows the bandwidth of the caches and RAM
as being normal (compared to
the other 965 PC). But still it runs like a Trabant stuck in first
gear.
I have used about 100 PCs over the last 15 years, and have not seen a
fault like this before.
It used to work OK a few years back, before taking a holiday in the
broom closet.
So I will scrap it, but I am really curious: what sort of fault can
slow a PC like so?
 
BW said:
I got out an old PC from broom closet.It has Gigabyte 965P mainboard,
Core 2 2666 and DDR2 667 RAM.
Now it is amazingly slow. I have a home-theatre PC also with 965
chipset, but only an 1866 MHz CPU and
that goes about 10 times as fast.
Everthing seems slow, from disk access to drawing graphics. Booting
and shutting down takes aeons.
It has linux installed. I checked "top" command and there are no
phantom processes using up all the CPU cycles.
And there is free RAM, it is not using swap disk.
I checked BIOS settings, and everything is optimum without
overclocking. I know if you do something like
turn off L2 cache, that is worth roughly 10% penalty not 10x.
I ran memest program and it shows the bandwidth of the caches and RAM
as being normal (compared to
the other 965 PC). But still it runs like a Trabant stuck in first
gear.
I have used about 100 PCs over the last 15 years, and have not seen a
fault like this before.
It used to work OK a few years back, before taking a holiday in the
broom closet.
So I will scrap it, but I am really curious: what sort of fault can
slow a PC like so?
Click to expand...

Are all your fans operating at speed? Maybe the CPU or GPU are overheating
slightly, and the CPU has throttled back (not sure if yours supports that or
not).
Any chance you have a hard drive diagnostic program? I had an old out-dated
server that was turned off for two or three years, and it took four or five
power on/off cycles before the HDD would spin up enough for it to boot. Once
I cloned it to a new drive, it worked fine again. Just a thought. . .
 
BW said:
I got out an old PC from broom closet.It has Gigabyte 965P mainboard,
Core 2 2666 and DDR2 667 RAM.
Now it is amazingly slow. I have a home-theatre PC also with 965
chipset, but only an 1866 MHz CPU and
that goes about 10 times as fast.
Everthing seems slow, from disk access to drawing graphics. Booting
and shutting down takes aeons.
It has linux installed. I checked "top" command and there are no
phantom processes using up all the CPU cycles.
And there is free RAM, it is not using swap disk.
I checked BIOS settings, and everything is optimum without
overclocking. I know if you do something like
turn off L2 cache, that is worth roughly 10% penalty not 10x.
I ran memest program and it shows the bandwidth of the caches and RAM
as being normal (compared to
the other 965 PC). But still it runs like a Trabant stuck in first
gear.
I have used about 100 PCs over the last 15 years, and have not seen a
fault like this before.
It used to work OK a few years back, before taking a holiday in the
broom closet.
So I will scrap it, but I am really curious: what sort of fault can
slow a PC like so?
Click to expand...

If an add-in card generates "run-away interrupts", that can drop
a computer to its knees. You really need to get tools which display
hardware counters as much as possible, to detect such things.

There were some chips, known to cause this problem. In other words,
certain chip designs actually had a bug in the interrupt signal.
So I'm not claiming a "card has failed". In some cases, 30% of a
certain chip exhibit the interrupt bug, and would cause the PC to be
slow.

You can try removing any excess cards, like PCI or PCI Express
cards that aren't being used for anything at the moment.

In the BIOS, you could disable the Firewire chip or a Promise
RAID chip or anything else you're not using to boot the computer.
The idea being, that when the chip is disabled, we hope any
interrupts can't get through.

But at least it sounds like you're headed in the right direction.
You correctly looked at cache state, and whether cache is enabled
or disabled. On some systems, mis-configured cache makes a *big*
difference.

Having a disk controller slip from DMA to PIO mode (about 4MB/sec
on reads), can have an impact on perceived speed. But then,
operations that are purely compute-bound, are unaffected by that.
A slow disk affects the feel of the machine, at least until you
do something which is compute-bound (uses the CPU, but no disk).

You can use something like SuperPI, selecting number of digits
to be larger than cache size, to ensure fair testing. Compare
the two computers, and see how they do. The test has a footprint,
where I think 1 million digits uses 8MB of RAM, while the maximum
number of digits might use 256MB of RAM. And at 256MB, no desktop
processor can hold the entire thing in L3 cache.

http://www.techpowerup.com/downloads/366/Super_PI_Mod_v1.5.html

On my E8400 (3GHz, RAM at DDR2-800) right now, using SuperPI 1.5

1 million digits = 15.469 seconds (8MB RAM allocated)
2 million digits = 37.407 seconds (16MB RAM allocated)
4 million digits = 87.609 seconds (32MB RAM allocated)

It's possible the 6MB L2 cache on the processor, is aiding
the 1 million digit case.

Try scaling the results by frequency, and compare to your two processors.
For the most part, this should be a compute bound test. Yes, the
disk light will flash, but I think the clock is stopped during
disk I/O.

Paul
 
I got out an old PC from broom closet.It has Gigabyte 965P mainboard,
Core 2 2666 and DDR2 667 RAM.
Now it is amazingly slow. I have a home-theatre PC also with 965
chipset, but only an 1866 MHz CPU and
that goes about 10 times as fast.
Everthing seems slow, from disk access to drawing graphics. Booting
and shutting down takes aeons.
It has linux installed. I checked "top" command and there are no
phantom processes using up all the CPU cycles.
And there is free RAM, it is not using swap disk.
I checked BIOS settings, and everything is optimum without
overclocking. I know if you do something like
turn off L2 cache, that is worth roughly 10% penalty not 10x.
I ran memest program and it shows the bandwidth of the caches and RAM
as being normal (compared to
the other 965 PC). But still it runs like a Trabant stuck in first
gear.
I have used about 100 PCs over the last 15 years, and have not seen a
fault like this before.
It used to work OK a few years back, before taking a holiday in the
broom closet.
So I will scrap it, but I am really curious: what sort of fault can
slow a PC like so?
Click to expand...

Start by treating the MB as if right out of the box (I'd leave the
cpu&heatsink alone) - as near to the MB-only as possible - for video,
a DVD or flashstick to boot from. Short the BIOS setting pins or
remove battery power. Also reflash/update the BIOS if it's still
slow. No fun replacing the CPU, but if you've a spare one within mb
spec's - that's another option. You'll then have given it every
chance to come up normally - short of replacing Gigabyte's mb support
chips with surface-mount wave soldering.
 
When you first pulled it out of the closet
and ran it up, did you have to reset the
BIOS settings? (CMOS settings?)

Do the SATA drive ports have an IDE mode, Legacy Mode or "Combination"
mode?

Set on in BIOS settings?
 
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