Gaming with Core 2 and CrossFire on 975X

We were so used to getting excited over AMD processor launches that we almost forgot what an important Intel CPU launch was like. You see, AMD and Intel behave very differently when at a dinner table preparing to eat their meals. AMD will eat when its partners eat; companies like ATI and NVIDIA get to share in the joy of a new AMD product launch as they are busy building chipsets for the new platform. That's why we get a new nForce chipset whenever AMD launches a new CPU. Intel on the other hand isn't as generous; Intel likes to eat first, and then whatever remains after it's nice and full can be scraped off the table and given to its partners. This is why today's launch is taking place pretty much exclusively on Intel chipsets, with retail products based on ATI/NVIDIA chipsets shipping in the coming months.

Intel's table manners aren't as nice as AMD's largely because they don't have to be. Intel has a lot more fabs than AMD, however they aren't all pumping out 65nm Core 2 Duos on 300mm wafers; instead many of them are still using old 90nm or 130nm process technology. It's not exactly economically feasible to keep converting all of the fabs to the latest technology as soon as it's available, so Intel uses up excess capacity in its older fabs by producing chipsets. AMD does not have this luxury so it depends on companies like ATI, NVIDIA, SiS and VIA for the platform side of things, and thus is much nicer at the dinner table.

Eating habits aside, what this means for us is that our only real options to test Core 2 Duo are with Intel chipsets. NVIDIA's nForce 590 SLI reference board for Core 2 Duo is in our labs but its BIOS isn't finalized yet so NVIDIA is asking us to hold off on using it for a couple more weeks. At the same time, we're hearing that we shouldn't expect any retail motherboards using ATI chipsets for Core 2 Duo motherboards until September at the earliest, once again leaving us with Intel.

Don't get us wrong; Intel chipsets are far from a terrible option. In fact, Intel continues to make extremely trouble-free platforms. It's not stability or performance that we're concerned about, as Intel has got both of those down pat. The issue however is multi-GPU compatibility.

You see, NVIDIA is a lot like Intel in that it wants to eat first or maybe, if the right people are at the table, at the same time as its partners. The problem with two companies that have identical eating habits is that no one ends up eating, and thus we have no SLI support on Intel chipsets. NVIDIA views this as an upper hand because honestly it's the only tangible advantage anyone has ever held over an Intel chipset since the days when Intel and Rambus were inseparable. If you want the best multi-GPU solution on the market you buy NVIDIA graphics cards, but they won't run (together) on Intel chipsets so you've got to buy the NVIDIA chipset as well - sounds like NVIDIA is trying to eat some of Intel's dinner, and this doesn't make Intel very happy.

Luckily for Intel, there's this little agreement it has with NVIDIA's chief competitor - ATI. Among other things, it makes sure that Intel platforms (or platform in this case, since it only officially works on the 975X) can support CrossFire, ATI's multi-GPU technology. Unfortunately, CrossFire isn't nearly as polished as NVIDIA's SLI. Case in point would be benchmarking for this Core 2 Duo article, which used a pair of X1900 XTs running in CrossFire mode. During our testing, CrossFire decided to disable itself after a simple reboot - twice. No warnings, no hardware changes, just lower frame rates after a reboot and a CrossFire enable checkbox that had become unchecked. Needless to say it was annoying, but by now we already know that CrossFire needs work and ATI is on it.

More than anything this is simply a message to ATI and Intel: if CrossFire had been in better shape, the high end gaming enthusiast could have been satisfied today, but instead they will have to wait a little longer for the first nForce 500 motherboards with Core 2 support to arrive (or settle for a nForce 4 board with Core 2 support).

Why does multi-GPU even matter? Given how fast Intel's Core 2 processors are, we needed to pair them with a GPU setup that was well matched - in this case we went with a pair of X1900 XTs running in CrossFire mode. With a pair of X1900 XTs we could run at 1600 x 1200 for all of our gaming tests, achieving a good balance between CPU and GPU loads and adequately characterizing the gaming performance of Intel's Core 2 line.

Encoding Performance using DivX 6.1, WME9, Quicktime (H.264) & iTunes Gaming Performance using Quake 4, Battlefield 2 & Half Life 2 Episode 1
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  • Kougar - Friday, July 14, 2006 - link

    I wasn't sure of the B2 Stepping 6 info because it has been impossible to find CPU-Z shots of this chip, let alone anyone reviewing them!!

    Mostly I just want to ensure Intel doesn't pull any surprises or OC limiting with them, at this point if the B2 Stepping 6 with that last round of bugfixing performs even the same as a Stepping 5 I'd be extremely happy!
  • redpriest_ - Friday, July 14, 2006 - link

    Thanks Wesley - my Core 2 Duo Extreme X6800 is definitely a Stepping 6, Revision B2 Conroe. It has a packaging date of July 5, 2006. I have all the multipliers unlocked, and I am stuck at around 3.466 ghz using multipliers only for stability. I am running on the Intel 975X BadAxe rev 304 with the latest BIOS.

    I haven't tried upping the bus from there, yet - I am using 1.4 volts; default voltage isn't dual prime 95 stable at 3.466 ghz, but is at 3.2 ghz.

    I haven't tried any intermediate voltages between there to test, so it's possible my Conroe is stable at 3.466 ghz at less voltage. I'll give that a try.
  • Kougar - Friday, July 14, 2006 - link

    What motherboard is this? Have you double-checked your RAM settings and memory ratio? I'd imagine setting a 1:1 ratio, using the most relaxed timings, and slowly ramping up the FSB would get you further. And do try less voltages... ;)

    That's my plan anyway, DDR2-800 memory speeds on a 1:1 ratio thanks to a 400FSB, 10x multiplier... :)
  • Kougar - Friday, July 14, 2006 - link

    Anandtech used Engineering Sample CPUs, so they would be B0 Stepping 4 or B1 Stepping 5 only. Only retail models will be B2 stepping 6...

    Did you change your cpu voltage any? Sounds like you didn't ;)
  • redpriest_ - Friday, July 14, 2006 - link

    I had to - 1.4 (1.35 real) to get to 3.466, and 1.5 to 3.733.
  • Wesley Fink - Friday, July 14, 2006 - link

    Did you OC by adjusting multipliers first? We could run the X6800 at 3.46 at 13 multiplier using stock voltage, but using 315 bus times the stock 11 multiplier required a small voltage increase. The easiest OCs used higher multipliers and modest FSB increases. The E Conroes are locked, however, and can only be overclocked by increasing the FSB.
  • redpriest_ - Friday, July 14, 2006 - link

    Yes, I tried using multipliers only, I haven't fiddled with bus speed yet.
  • Kougar - Friday, July 14, 2006 - link

    First, the X6800 is selling at NewEgg, and they are price gouging it for all it's worth. Still listed in stock after having been up for 3+ hours...

    What a great way to start the day... Thank you Anandtech for this great article! Supurb! Now I have to agree with the poster above me, some info on the E6300 overclocking would about round out my curiosity!

    I have a question though, do y'all or anyone else have some CPUZ shots of a retail shipping Conroe? I believe this are supposed to be revision B2 stepping 6??

    As for the expected skeptics, my saying the numbers appear to jive won't mean anything... so I'll just say there are over 25 reviews out now of the Core 2 Duo released today. :)
  • mAdMaLuDaWg - Friday, July 14, 2006 - link

    I'm curious on if you tried OCing the E6300. What was the highest stable speed you were able to get.
  • xsilver - Monday, July 17, 2006 - link

    for those who dont want to read the xbit labs article
    the overclocking of the e6300 is limited by the motherboard - eg. cant get the board to boot at any higher than 420mhz fsb

    we may have to wait for nvidia's core2 solution to see higher fsb's

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