Fast Processor vs. Dual Core/Quad Core

It seems like the clock speed on these multi-core processors is pretty low. Are you sacrificing game performance if you go from say a single core Athlon 64 4000+ down to a 2GHz or whatever they run at dual core processor?

It sure seems like that would be the case given most games today probably aren’t using both cores or wouldn’t know how to use them. I’d hate to upgrade only to end up with a slower machine. I guess I just don’t understand the current rush to multiple cores when it seems like there wouldn’t be any benefits until software could take advantage of it?

The clock speeds are lower or about the same, but they’re more efficient at doing ‘work-per-clock’, so they’re still faster overall.

It’s getting harder and harder to keep pushing that clock rate up, so going to multiple cores is just another way of increasing processing power for a reasonable cost, even if it is more difficult to take advantage of.

First, ignore the AMD processor product numbers. They’re meaningless.

Second, the fastest single core A64 available is the 2.4GHz 4000+. Dual core A64’s go to 3.0GHz.

That’s not so true with the Intel line in the pure clock frequency sense. You can get Pentium 4’s as fast as 3.8GHz. But a dual core Core 2 is considerably faster than a P4, and runs cooler.

It’s worth adding that games are increasingly starting to make use of dual core processors. The lead programmer of Bioshock for instance recently said that it would make productive use of a quad core processor, even.

E6420 is 2.13GHz, E6600 is 2.4GHz and E6700 is 2.66. Per core. There’s also
the matter of all that cache - 2MB for each core helps a bundle.

What the actual frequency means compared to similar singlecore CPUs, I dunno,
but they’re certainly very efficient. You also get the added bonus of a much
more responsive system when one core is loaded with a game. I don’t have
anything that’s really good at taxing both cores, so the “spare” core is put to
good use giving me my desktop when I need it. Haven’t found any games that
at all seem slow on an E6600+8800GTS.

Not really games related, but my new Core Duo work laptop is noticeably faster than my previous Pentium 4 work PC, main because all the crap that we have to run for work (norton av/firewall, firefox, IDE, clearcase, yahoo IM, outlook, 1-2 more other apps) were fighting over the single CPU before…30% CPU constantly. With the Duo Core, it feels as if one CPU is handling my IDE, and the other CPU is doing the rest of the crap. Therefore, the IDE is much more responsive.

When I upgraded my machine earlier this spring, I found the CPU (& video card) comparison feature at Tom’s Hardware helpful. You can see that in many applications, a multi-core processor with a lower clock speed will outperform a single-core with a higher speed. Right now, you see greater benefits of multi-core over single on tasks like encoding, but as more games are released that make use of multiple processors, there should be additional advantages there as well.

OK, that’s six replies, but I don’t think anyone answered the specific question. I was aware of the Bioshock comments, but what about other games, specifically things that used all that processing power of the faster single-core processors. Games like Gothic 3 or Oblivion or Battlefield 2/2142? Are those going to be slower on dual core?

IOW, “Are you sacrificing game performance if you go from say a single core Athlon 64 4000+ down to a 2GHz or whatever they run at dual core processor?”

The issue isn’t simply performance ability in general. The extra cores only see use when the application running uses multithreaded programming, so games (and other aps) will only go faster if there are enough threads jumping around to be distributed to the cores - if no multithreaded programming is used, only one core can actually process it.

However, one advantage that hasn’t been talked about is load. If the OS takes enough advantage of the multiple cores, then its tasks can be distributed while the running game can play around with one processor. This would probably show a bit of a speed increase… I think. I haven’t done much thread programming, so this is mostly conjecture.

There are specific cases where you could get worse performance, mainly when you’re staying within the same CPU family and generation. E.g., an Athlon 64 X2 4200+ would be slower than the one you mentioned because it’s the same family, so it would get similar performance-per-clock, but has a slower clock and smaller cache when looking at a single core.

But in general, no, the per-core performance of a current-gen dual-core processor will be faster than that of an older single-core, even if the clock rate is a bit slower, because of other architectural improvements.

(All assuming that the game is single-threaded and CPU-bound, of course. Though even then there might be some benefit from having the kernel and drivers running on the other core.)

Everything is faster than ever. Responsiveness is wonderful. Picking a singlecore now is just dumb ;)

Comparing the single-core A64 4000+ (2.4GHz) vs dual-core A64 X2 4000+ (2GHz), there will be times where raw CPU speed is more important than a second core. But it’s a moot comparison at this point: going forward, basically all CPUs but the lowest-end ones will be multi-core.

Also, the clock speed alone is meaningless: the A64 outperformed the P4 at lower clock speeds; now the C2D outperforms the A64. You have to look at actual benchmarks and what you’ll see is that even the entry-level C2D leaves single-core A64s in the dust in pretty much everything.

It has already been said here, but clock speed alone is meaningless when comparing chips with different architectures, pipelines and clocks per instruction profiles.

I went from a 3.4ghz P4 on my main system to a 1.86 ghz C2D and even with legacy applications and games that are hopelessly single-threaded, the 1.86 ghz C2D runs rings around the 3.4ghz P4. Even if you somehow disabled the 2nd core, the C2D at 1.86 is faster than a 3.4ghz P4. When games start actually taking advantage of the extra cores, that will just be gravy on top of the other improvements. The C2Ds also run cool enough that with a good motherboard and memory you can overclock them to ridiculously high speeds.

Core 2 Quad Q6600 is dropping to $250 in July, so don’t buy a C2D E6600 now and feel like a dumb-ass later. There will also be an E6800 chip for $250, which is if you want dual core instead of quad core, but at higher clock-speed (2.8GHz I believe). I think the E6800 will also be 1333MHz FSB.