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Old 2007-10-02, 01:02   #1
Jud McCranie
 
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Default Laptop running at 1/3 speed

Hello, I bought a Toshiba laptop last week, and it is running about 3 times slower than I expected on
Prime95. It has a 1.73 GHz dual core Pentium. It is working on a LL test in the 40,000,000 range and it is going to take 3 months. I ran the benchmarks and they seem to be 3 times slower than other CPUs of the same speed. Under task manager, Prime95 is getting 49-50% of the CPU, so it is getting all of one core.
The machine has only 1GB of ram and I've ordered an upgrade to 2GB, but I don't expect it to make that big of a difference.
Is it normal for a laptop to be this slow, or is this expected?
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Old 2007-10-02, 02:23   #2
bsquared
 
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Quote:
Originally Posted by Jud McCranie View Post
Hello, I bought a Toshiba laptop last week, and it is running about 3 times slower than I expected on
Prime95. It has a 1.73 GHz dual core Pentium. It is working on a LL test in the 40,000,000 range and it is going to take 3 months. I ran the benchmarks and they seem to be 3 times slower than other CPUs of the same speed. Under task manager, Prime95 is getting 49-50% of the CPU, so it is getting all of one core.
The machine has only 1GB of ram and I've ordered an upgrade to 2GB, but I don't expect it to make that big of a difference.
Is it normal for a laptop to be this slow, or is this expected?
Are you running it on battery power or plugged in? I know some laptops run in "power saving mode" when run on batteries. That feature can significantly cut into performance.
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Old 2007-10-02, 03:20   #3
Jud McCranie
 
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I should have mentioned that - I'm running it plugged in.

Also, I set the video to "best performance" but that didn't seem to make a difference. One thing - it shares main memory with the video, but I don't know how much that affects it. It is running Windows Vista Home Premium.
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Old 2007-10-02, 17:47   #4
Cruelty
 
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Please post your benchmarks.
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Old 2007-10-02, 18:01   #5
petrw1
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Default Food for thought

I'm not suggesting this is your situation but I only present this to suggest your answer might be in the last place you would consider looking:

I just finished working on a PC that was performing at less than 40% expected. It was a P4 3Ghz with 1GB Ram but still doing a LL test in the 36M range at close to .2 seconds per iterations when I expected closer to .07 seconds according to experience and the benchmarks.

I looked for the obvious:
I scanned for SPYWare, SPAM, Viruses ... and found lots but it made no difference to the performance.
Task Manager showed 99% going to primenet ... so no runaway processes.

Finally I gave up on performance and tackled her other problem: Her CD and DVD drives were not accessible ... to make a long story short, they were chained together but both were set as SLAVE drives. Once I fixed that the drives both worked ... AND ... the performance improved to the expected level.
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Old 2007-10-02, 18:58   #6
Jud McCranie
 
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The CD drive seems to be working OK.

I ran the benchmark, and it says that it wrote to the file results.txt. However, that file is not in the Prime95 folder. Also, the intermediate data files are not in that folder and the WorkToDo file gives a different exponent than the one it is actually testing. A Search doesn't find the results.txt file.

None of the files are dated afyer 9/26. I did change the name of the computer user after I started Prime95.

Maybe I should uninstall Prime95 and reinstall it?
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Old 2007-10-02, 23:15   #7
Prime95
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I had a similar problem with my 2 GHz Dell Inspiron laptop. Throttlewatch showed that I was not slowing down due to overheating. SpeedStep was of no help. Yet the OS and prime95 showed I was running at 1.2 GHz (yet the slowdown was far greater than 40%).

I whipped out google: "slow dell inspiron" and was lucky enough to find the solution. Apparently, this model can develop bad fan sensors. Consequently, the BIOS throttles back the CPU. There is an undocumented feature: the fn key + Z makes the CPU run at full speed again - for a little while. Then I found a dell-only utility that forces the fans to run at full speed all the time rather than thermally controlled. This setting also stops the BIOS from slowing the CPU.

So I can only recommend googling "slow Toshiba laptop" and maybe you'll get lucky too.
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Old 2007-10-02, 23:46   #8
Jud McCranie
 
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I'll look for that. I ran some other benchmarks, and Prime95 was the only one that seemed slow.
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Old 2007-10-03, 00:53   #9
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Considering you have a dual core processor, are you running two instances of Prime95 or a multi-core version?

According to the calculator on http://www.mersenne.org/bench.htm a pentium4 @ 1730Mhz for a 40M bit mersenne will take "83 days, 7 hours, 15 minutes".

(666 posts )

Last fiddled with by paulunderwood on 2007-10-03 at 01:19
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Old 2007-10-03, 02:17   #10
Jud McCranie
 
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I'm only running one instance on that computer. However, you may have just gotten the answer. The CPU is a "Pentium Dual Core" and Belarc says it is a "Intel Core Duo". Is that more like a dual Pentium 4 than a "core 2"?
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Old 2007-10-03, 02:31   #11
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Re: http://en.wikipedia.org/wiki/List_of....2C_65_nm.29_2

From your frequency specification it looks like you have a 32-bit dual core "Core Duo T2250", but I can not see it on the "bench page."

But I see iteration time for 39M+ FFT:

0.1037 secs for Pentium 4 (512Kb cache) @ 1800 MHz
0.1522 secs for Core Duo @ 1820 MHz

So yours appears to be ~50% slower than an equally clocked desktop P4.

A Core2 is much quicker and is 64-bit

HTH

Last fiddled with by paulunderwood on 2007-10-03 at 02:46
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