Lately I’ve been thinking about AMD’s recent release of its desktop quad-core range of Phenom CPUs. Why does everybody bag them? The entry level model is quite cheap, and surely four cores are better than two, even at a slightly lower clock speed, right? Well, I decided to find out for myself, and today I will present you with my findings.
I have in my hot little hands a 2.2GHz Phenom X4 9500 processor, which can currently be had for around $280 from reputable online retailers (I got mine from PlayTech).
First let’s have a look at what the chip offers on paper then we’ll put it through the paces and see what this new silicon can deliver to us.
From AMD’s new range of “K10” chips, the Phenom 9500 runs on the same 200MHz HTT bus speed – AMD’s equivalent of Intel’s FSB - as all other AM2/AM2+ CPUs, with an 11x multiplier which brings it up to a final 2200MHz stock CPU speed.
With a compatible AM2+ motherboard you can take advantage of the increased HyperTransport link - up from 2GHz to 3.6GHz; this doesn’t provide much if any performance boost as the HT link would rarely bottleneck on AM2 boards, but it’s good to have the headroom nonetheless.
The cache architecture has also been altered slightly from the K8 series of CPUs (they skipped the “K9” nomenclature, probably due to marketing reasons); each core still has its own amount of L2 cache, 512KB in this case, but a third level of cache has been added of 2MB which can be dynamically assigned to one or all four cores. This gives the processor the best of both worlds as far as cache goes; faster, lower-latency L2 cache and larger, more bandwidth-friendly L3 cache.
This shows improvement most quantifiably in cache-sensitive applications or benchmarks like SuperPi, but can also provide a nice boost for everyday gaming as well.
Today I’ll be comparing the 2.2GHz Phenom 9500 with the 2.2GHz Athlon X2 4200+ (Windsor core, 2x512KB L2 cache), both at stock speeds and also overclocked to 2750MHz, and then I’ll also throw in the results of an Intel Q6600 @ 3000MHz just for comparison. Whether Phenom beats the Q6600 clock-for-clock is somewhat irrelevant, seeing as the Intel chip will overclock to this level on pretty much any motherboard with stock voltages and stock cooler. I don’t expect the AMD chip to compete with the Q6600 in many of these tests so I won’t discuss its results too much, but I’ve thrown it in there for reference anyway (and to shut us Intel fan boys up -Ed).
I’ll be plugging the AMD chips into the excellent GA-MA790FX-DQ6 motherboard from Gigabyte. This currently e-tails just under the $400 mark, but there are plenty of cheaper AM2+ compatible motherboards available such as the ~$80 Asus M2N MX SE Plus for the budget gamer, to the more featured-packed ~$155 Gigabyte GA-MA770-DS3 for the mainstream crowd. The overall performance isn’t really affected by the motherboard, although some boards may hinder the overclock potential of your chip.
The graphics card used is an overclocked 512MB HD 3850 with a core speed of 749MHz and RAM speed of 2000MHz, which is pretty much equivalent in performance to an HD 3870 as it uses lower latency GDDR3 RAM instead of the higher latency GDDR4 RAM on the more expensive series of cards. I’ve set the RAM to run as close as possible to DDR2-800 speed with CL4 for all AMD configurations, and set it to DDR2-1000 CL5 for the Intel system.
Lastly, I've disabled the performance-sapping TLB errata patch for all tests, and it's such a non-issue I don't even want to talk about it, except to say that no instability was experienced, nor did I expect there to be in the first place.