September GPU Tidbits: SLI, Master Cards and X800by Kristopher Kubicki on August 26, 2005 7:19 PM EST
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NVIDIA's Low End SLI Game Plan (And Other GPU Tidbits)
Over the last three months (particularly just before the launch of the GeForce 7xxx series), we heard a lot from manufacturers with regard to the push for low end SLI components. This included reducing the cost of SLI motherboards on Intel and AMD platforms, releasing new low end SLI video cards and even removing the paddle cards / bridge connectors. A dollar here and a dollar there eventually leads to big savings, right?
Whether or not you agree with the philosophy of SLI, reduction on motherboard and card costs is obviously a bonus for everyone. Once we start removing oddities like the bridge chip and SLI toggle paddle, SLI begins to act more like a scalable upgrade path than a select instance upgrade path. So what's the game plan for low end SLI on NVIDIA's behalf?
The first is to introduce GeForce 6600 SLI and GeForce 6600LE SLI. Both of these cards are already hitting the streets as we speak - SLI has been available on the 6600 since Detonator 77.72 and on the 6600LE since 77.74. The 6600LE cards we have seen (specifically the XFX 6600LE) still come with the bridge connector slot on the top of the device, but this is completely unnecessary as even a dual eight lane (but sixteen slot PEG) PCIe channel is sufficient for the bandwidth needed in SLI. Let's take a look at NVIDIA's low end component roadmap:
|NVIDIA Low End Roadmap|
|Card||Core Clock||Memory||Notes||Mass Production|
|GeForce 6600||450MHz||128MB or 256MB 500MHz DDR||SLI||Now|
|GeForce 6600LE||400MHz||128MB 500MHz DDR||SLI||Now|
|GeForce 6500||400MHz||128MB 700MHz DDR1||TurboCache Available||Now|
The GeForce 6500 is a little bit of an unusual animal since vendors can opt for TurboCache or standard memory configurations, even though it is based on an NV43 core. The card comes with a 128MB buffer operating at 700MHz, but also has the ability to switch to a TurboCache configuration. Our first reports claimed that performance of the GeForce 6500 was somewhere in between a GeForce 6200 and a GeForce 6600LE, but looking at the clocks alone it seem as though the 6500 has a bit of an edge over the 6600LE. Unfortunately, there are no SLI capabilities (yet) on these cards, but we have seen off-the-record SLI implementations of GeForce 6200, so it would probably be safe to assume someone, somewhere, somewhen will be able to run a 6500 in SLI mode.
GeForce 6600 SLI is something we actually knew about back in June, but it's been slow for adoption since (at the time) a bridge connector was needed. Our friends at Prolink actually had samples of a 6600 in SLI configuration with the bridge connector, but with the newer drivers this is completely unnecessary.
Multi-GPU Cards and Crossfire
That's not all; there's more SLI news. Even though we haven't seen Crossfire in retail channels yet, manufacturers who have early samples of the motherboards are reportedly hacking drivers to get various dual GPU video cards to work on Crossfire motherboards... without the SLI bridge connector. Obviously, the implication here is that NVIDIA's SLI should also work on any GeForce cards in a dual PEG motherboard - NVIDIA chipset or otherwise. (Higher performance cards would likely take a performance hit by sending data over the PCIe bus, however.) In all likelihood NVIDIA will simply flex its muscles at the vendors who attempt to release their own drivers or configurations that allow NVIDIA SLI on Crossfire (much as we saw with nForce4 SLI on nForce4 Ultra a few months back). However, if not, you can be sure you'll see some interesting benchmarks on AnandTech.
X800GT Sold Out; Master Cards Soon (Really, We Think, Maybe)
Oddly enough, even though the X800GT got incredible resentment from the majority of our readers, the fact is that ATI sold a ton of chips in a very short period of time. So much so that Tier 1 partners are having trouble securing more chips, which is probably the primary reason why X800GTO showed up on the radar. A few Tier 1 guys that we all know and love are actually countering the X800GT with extremely favorably clocked 256MB X800 vanilla cards instead. An X800 vanilla running at say, 800MHz memory clock would still not be able to match the memory bandwidth of a near-1000MHz GDDR3 X800GT, but the additional pipes give it a much better fill rate. More details on that in the near future as well...
Recently I had the opportunity to sit in an OEM GPU briefing. The first 50 minutes of the meeting were incredible slides of GeForce 7xxx sales figures, SM3 features, new products, driver rollouts - the usual. The last 10 minutes of the meeting were spent going over ATI's cryptic roadmap slide. Aside from the fact that nearly the entire roadmap was covered in question marks, we were able to discern some information about the X800 Master cards and their rollout schedules. Here is what we saw:
|ATI Master Card Roadmap|
|Card||Core Clock||Memory||Notes||Mass Production|
|X850XT Master Card||400MHz||1080MHz 256MB GDDR3||DMS||September|
|X800XL Master Card||400MHz||980MHz 256MB GDDR3||DMS||September|