Vista vs. XP for LL

[Rodrigo]

A couple of weeks ago I bought an HP Compaq dx7500 tower with an Intel Core 2 Duo E7600 processor (a steal for the price I paid).

I'm multibooting it with Windows XP and Vista (both x86), and (of course) it's running Prime95 (v26.6) whichever OS I'm using. After number-crunching on Vista for about ten days, I just switched back to XP and restarted Prime95.

Surprisingly, there is quite a difference in Prime95's performance between Vista and XP: whereas the 50M-level LLs the box is working on had per-iteration times of approximately 0.058 seconds in Vista, in XP they're at 0.079 seconds.

Both systems are new, clean, and lean. Other than the OS, the only active software difference between them is that I have McAfee Total Protection on the XP side, and Avast! 7 on the Vista side. Could this alone account for the performance difference, or is the difference more attributable to the operating systems? (Unlike the Vista setup, the XP setup also has MS Office installed, but nothing's open and no Office processes seem to be showing in Task Manager.)

Anybody have insight on this?

Rodrigo

[LaurV]

McAfee is known as one of the slowest tool on the domain. There is a post of mine somewhere around here where I was pleading for nod32 from Eset. I have no idea about the impact McAfee has on P95, but this could be easy to see, you can disable "real time scanning" and see if there is any difference. This is the first thing you should do. Another reason could be the 32/64 thing, most probably your xp is 32 and vista is 64. (?)

Anyhow, letting apart the P95 work, talking only about using McAfee as antivirus/protection, my advice is: don't. There are plenty of faster/better solutions. Check virus bulletin. Pick one who had at least 6-10 submissions for vb100 award, and passed all of them. There are not so meany choices, another two or three beside of Eset's nod32 (and none with so many, I am using it for many years and I am quite happy with it, it has one of th ebest heuristics to detect new -unknown- viruses, contrary to McAfee which relies more on signature, it can detect the threats after they are "known" and somebody "patches" the code with new signature/behavior files).

[axn]

Are they running the same exponents (or at least, the same FFT size)? Is the CPU underclocking under XP? Are you running P-1 stage 2, by any chance?

Bottomline is, the OS has practically nothing to do with how fast P95 runs. So, there must be some specific (non-OS) factor that's causing it -- find it and fix it.

[petrw1]

Originally Posted by LaurV

McAfee is known as one of the slowest tool on the domain. There is a post of mine somewhere around here where I was pleading for nod32 from Eset. I have no idea about the impact McAfee has on P95, but this could be easy to see, you can disable "real time scanning" and see if there is any difference. This is the first thing you should do. Another reason could be the 32/64 thing, most probably your xp is 32 and vista is 64. (?)

Anyhow, letting apart the P95 work, talking only about using McAfee as antivirus/protection, my advice is: don't. There are plenty of faster/better solutions. Check virus bulletin. Pick one who had at least 6-10 submissions for vb100 award, and passed all of them. There are not so meany choices, another two or three beside of Eset's nod32 (and none with so many, I am using it for many years and I am quite happy with it, it has one of th ebest heuristics to detect new -unknown- viruses, contrary to McAfee which relies more on signature, it can detect the threats after they are "known" and somebody "patches" the code with new signature/behavior files).

I find that often McAfee is hogging an entire core for "Real Time Scanning" on my Quad.

[Rodrigo]

Originally Posted by LaurV

McAfee is known as one of the slowest tool on the domain. There is a post of mine somewhere around here where I was pleading for nod32 from Eset. I have no idea about the impact McAfee has on P95, but this could be easy to see, you can disable "real time scanning" and see if there is any difference. This is the first thing you should do. Another reason could be the 32/64 thing, most probably your xp is 32 and vista is 64. (?)

LaurV,

Thanks for the advice. I'll let the McAfee trial period run out and then get something else.

Both of the OS's on the machine are 32-bit versions.

Rodrigo

[Rodrigo]

Originally Posted by axn

Are they running the same exponents (or at least, the same FFT size)? Is the CPU underclocking under XP? Are you running P-1 stage 2, by any chance?

Bottomline is, the OS has practically nothing to do with how fast P95 runs. So, there must be some specific (non-OS) factor that's causing it -- find it and fix it.

axn,

Huh, interesting. It must be the security suites, then.

Yes, they are the exact same two exponents in the same machine. The difference is which OS I booted into (and then Avast vs. McAfee).

I don't know about underclocking. (How does one find out?) What kind of situation would cause a CPU to underclock under XP but not in Vista?

Both factors (the machine has two cores) are currently being LL'd.

Rodrigo

[Rodrigo]

Originally Posted by petrw1

I find that often McAfee is hogging an entire core for "Real Time Scanning" on my Quad.

Whoa!

In my case, though, it's not that McAfee is periodically claiming a core to do background scanning or anything -- it's just a steady 0.079 seconds per iteration, compared to 0.058 seconds when I'm running the Vista side.

Rodrigo

[LaurV]

What does Task manager says? 99% for P95? If not, who takes the rest? I mean in in XP.

[Rodrigo]

Originally Posted by LaurV

What does Task manager says? 99% for P95? If not, who takes the rest? I mean in in XP.

Task Manager shows Prime95 at 99%.

When I get a chance to, I'm going to suspend/disable McAfee and see if it makes a difference in the per-iteration times.

Rodrigo

[axn]

Originally Posted by Rodrigo

I don't know about underclocking. (How does one find out?)

CPU-Z could probably tell you.

[Rodrigo]

Thanks, axn. I'll download CPU-Z and check it out.

Rodrigo