Quote:
Raapys said:
To my knowledge there's no real cons against quad core( except price, and bigger cooling and power requirements ) compared to dual core. Intel's quad core CPUs, the only quad cores available at the time, are simply two of their dual cores put together on one chip. Given the same clock frequency, a quad core and a dual core will perform equally in applications/games that only support one or two cores.
The catch here is, as mentioned, the price. The 3ghz dual core costs the same as the 2.4ghz quad core.
Personally I think it's only about a year or so before most( if not all) new games released will take some advantage of quad core, though.
|
The other con is the amount of die space available for on-chip cache. Normally about 50-67% of the space on a modern microprocessor is taken up by cache; if you take a dual core and squeeze another two processing units onto the chip, you are either going to: A) cut out some parts of the processing cores, B) reduce the amount of total cache, or C) take a lot more power. The only way to get around this is to reduce your process size (e.g. 65nm to 45nm), but then you can use the same process on dual cores, and you end up with the same trade-off.
For intel chips, the most apples-to-apples dual v. quad comparison I could find is the E6850 (dual) v. QX6850 (quad). Both have the same FSB @ 1333MHz, both have 32kiB L1 and 2MiB L2 per core, and both operate overall at 3.0GHz. The difference is power: the E6850 takes 65W @ 0.962V-1.350V; the QX6850 takes 135W @ 1.100V-1.372V. That means you'll need a lot more cooling for the quad core. On benchmarks, doing raytracing (by nature a multi-threaded process) or other image manipulation in 2d or 3d gives around 10-25% advantage to quad core. Compilers, web servers, etc. actually do better with dual cores, compression gives <10% advantage to dual core except with h.264 which seems to give a nearly 50% advantage to quad core. And then games... the differences are so small as to be negligible.
And then comes the cost: QX6850 will cost you around $1000. E6580 about $250. And power consumption is 69W v. 17W while idle, and 136W v. 67W under load. Which means that the E6850 will cost less to run under full load 24/7 than the QX6850 if it is idle 24/7. At my electricity prices (~$0.11 / kWh), that amounts to $66.50/year to run the quad core 24/7, vs. $16.50/year to run the dual core.