Need quick tutorial on today's PC processor power

I’m in the IT field but not up to date on hardware. I haven’t bought a PC for a few years, when you just had to look at processor cycle speed (more or less; I know that one CPU’s GHz is not another CPU’s GHz). Now the big thing are the dual- and quad-core machines.

As an example, I am browsing Dell and here are the options they offer for processors on their XPS 420. The most expensive option by far is a 3.0 GHz option, and I can’t tell if it’s multi-core or single-core. They offer a 3.16 GHz option for $1,050 less, which I’m assuming is a dual core.

Do the speed ratings represent each core in a multi-core processor? That is, is a duo at a higher cycle rate less powerful than a quad at a lower cycle rate?

How well will my older applications take advantage of a multi-core configuration? Does Vista take care of this for me or do the applications have to be written for it to optimize performance?

And what the hell kind of configuration is that last one and why is it so expensive?

Yes, the clock rate is for each core. And a higher clock rate dual-core CPU may or may not perform better than a lower clock rate quad core depending on the application being tested and the architecture of the two CPU’s in question.

Older apps will likely NOT take advantage of multiple cores. For a single application to take advantage of multiple cores it needs to be optimized for the task and almost certainly threaded - that is programmed so as to be able to run multiple functions simultainiously. This is usually difficult and time consuming depending on the complexity of the program/the task that is being handled.

What a modern OS WILL do with a multi-core CPU is to try and dynamically load background services and user run applications onto idle cores. This translates into a smoother more responsive experience for the end user.

That last processor is a high quality dual core processor. The main draw of it is in it’s unlocked clock multi-plier. Someone who overclocks their system can push this processor to VERY high clock rates without putting too much stress on other systems components (by not having to raise the system bus too high). I’m 90% sure that Dell will not let you overclock your system through their BIOS. So unless they overclock the system for you or they make an exception in the case of this system, you wouldn’t be getting your full money’s worth here.

The option for $1,500 less is a CPU with a much lower overclock potential, both in terms of quality and clock multiplier. I believe there is also a difference in architecture/die size (and therefore efficiency and power consumption).

Like Kinthalis said, application design plays a huge role in determining how well a quad core or dual core will really perform for you. Also a major factor is how you use your applications. If you’re the kind of person who likes to run a lot of CPU-intensive tasks at once (say, encoding some videos while running a huge batch job in Photoshop and simultaneously playing a high-end game), then a quad core will be a huge boost, even if each individual application is single-threaded, since several applications can each run on their own CPU core. Of course, at this point disk access will definitely be the biggest bottleneck, so you might need several hard drives as well to see the best performance. :stuck_out_tongue:

If, however, you tend to only use one CPU-intensive application at a time, chances are a quad core will not be a big improvement over a dual core for you. As time goes on, more and more application developers will (by sheer necessity) begin writing applications that can make full use of several threads, but right now what you would probably wind up with is one or two cores running at 100%, and the other two or three completely idle.

As for that last configuration, that’s one of Intel’s “Extreme” processors - basically just the best-performing of a given Yorkfield batch, blessed with an unlocked multiplier and sold to suckers – err, enthusiasts :wink: – at a premium price. And speaking of price, Dell overcharges for just about everything. The last few computers I’ve bought have been moderate to high-end PCs I’ve assembled myself, for which I would have paid anywhere from $500 to $1200 more had I purchased equivalent machines from Dell.

The QX9650 is not only faster, but has a larger cache, talks to the memory faster, and is unlocked if you want to overclock.

The Core 2 Duo processors are dual core whereas your current selection is quad core.

In fact, the QX9650 is a quad-core processor (as the Q moniker suggests) with a large cache, which will deliver blistering performance for multi-threaded applications.

Personally speaking, I would choose either the currently selected processor, or the slightly cheaper dual-core 8400. For most applications and everyday use, that will be plenty.

oops, you’'re right, that’s the high end quad core.