Dual Proc vs Dual Core (and more....)

hi chrishow,

While hyperthreading will never get close to dual core performance, it does certain things like make your system responsive enough to avoid that "This application is not responding" message. If you do run multiple applications at the same time, Hyperthreading will be more desirable over a processor which isn't.

As for your AMD vs Intel question, it depends. Intel is leading in the video and media encoding applications, and AMD is ahead in the gaming and some office applications department. However, don't take this to mean that the lead is really that huge. Ordinary users won't notice much of a difference; only those who benchmark (the digits decide here, even if it's just a very small difference) and overclockers pay attention to the smallest detail.

Regarding Windows XP 64-bit, not yet a good time to go with. Driver support is still weak and even though I have an AMD64 processor, I don't use 64-bit OSes at all. I do hear that 64-bit versions of Linux are good, but I don't know if they are practical enough for use in the mainstream.

One more thing. In the dual-core arena, AMD still has the lead with it's Athlon64 X2 family of CPUs. However, Intel will be making some adjustments with the Pentium D 900 Presler. This is an interesting article you may want to read:

http://www.tomshardware.com/cpu/20051010/index.html

I am an advocate of AMD's dual core implementation, since it seems to outperform Intel's: http://www17.tomshardware.com/cpu/20050603/index.html

The top of the line Intel Pentium-D 840 EE is both dual core and hytperthreading, so it will appear as if there are 4 processors.  This is probably the highest performing desktop cpu, but it is not cheap.  You can also step up to server class multicpu machines with Xeons and Opterons, but they are also are expensive and require ECC RAM.

>>Win XP 64 bit -- not ready for prime time.   Simply no real application base, and running 32-bit apps on XP-64
>>is actually slower than running them on XP Pro.

I must disagree with this opinion.  My experience with x64 Edition of XP is that it is excellent and ready for "prime time" with a single exception.  Device driver support is still lacking.  But if your hardware is among the supported, you get excellent performance with 32-bit software and a huge upside with 64-bit applications which are rapidly appearing.  My tests show that 32-bit apps run 10-15% faster on the same box when running under x64 vs. 32-bit XP.  You can also pack as much RAM into your x64 box that you can afford and Windows will use it all.  You're not limited by the 2GB max RAM problem with 32-bit Windows.  Granted, 32-bit apps are still limited to 2GB of RAM (with a 4GB virtual space) but under x64 Windows _each_ application can have up to 2GB of physical RAM.

If you run RAM-hungry applications this is a big upside.

Also note that 16-bit apps cannot run on an x64 machine.  If you still have any old legacy DOS or WIN16 apps, they will never run on x64.

Don't waste the money on WinXP 64 bit. Wait till Vista comes out. Lack of drivers and programs (Anti-Virus primarily) is a big hinderance. 32 bit apps that work at the kernel level will NOT work.

Athlon64 X2 may be ahead of the Intel Pentium D but the price also reflects that.

If your turnover rate on desktop machines is 3 years, I would definitly get a dual core 64 bit processor. This will leave you room for software and/or OS upgrades in the future.

Based on your description your bottleneck is speed of main memory.

When you buy new computer be it Pentium-D or Athlon X2 you will buy 800MHz RAM alongside and it will be twice as fast as current 400MHz RAM chips in computer.

About same is to be said about disks, not twice, but 1.5 times faster due to improved manufacturing.

Hyperthreading is special microcode in processor which lets two processors work to saturate it's execution resources, which was not possible with compilers made two years ago, but now is not so essential.

Office is multithreaded, so it will gain from more processors, in case of hyperthreading read before. Maybe next version will not be impacted by that.

Before you buy you should evaluate whether amount of RAM in your computer is enough and how much will be great. With 512 it sometimes swaps to disk, but if performance is critical at all times I suggest 1G (but better explore your application setup)

Thanks to everyone for their advice and information.

We will be purchasing a HP branded box, in line with company standards, so I am somewhat tied to what processors they can supply in their high-end desktop and workstations.

My current processor choices are as follows:

Intel Pentium D 820, which is 2.8GHz, 2 x 1mb Cache (no HT)
OR
Intel Pentium 650, which is 3.4GHz with HT, 1*2mb Cache

I’m leaning towards the D820, but as a final question on this subject – am I likely to see far better performance on this 2 * 2.8 dual core over the single core 3.4 with HT?

I will proabably be installing 2gb in whichever machin I choose.

If you're doing a lot of tasks simultaneously (which it sounds like you are), the dual 2.8 will probably be better in handling the load.  The 3.4 with HT is good with a few simultaneous apps, but if they each demand a lot of cpu (which real-time spreadsheets do), the single cpu will top out.  I use a dual 2.2 Xeon myself.

Pentium-D is not hyperthreading it is advertized as dual-core.
Compaq dx* High-End Business workstations do have Athlon 64 inside. It heats up significantly less giving same computing speed.