Take a look at the numbers from this early Granite Bay review.
Other boards may end up doing a bit better (the review properly did not give big overclocking kudos to this particular board), but this will give you an idea of what to expect (and not expect) from these boards:
1) GB running at stock isn’t going to do any better than RD1066: Whether it’s dual-channel DDR266 or dual-channel RD4200; it’s still the same maximum bandwidth: 4.2Gb/sec. There’s overhead coordinating two sticks of anything. So it shouldn’t come as a surprise to find out that both do about the same.
2) Where GB shines is in overclocking, but it’s not blinding You’ll only see more-than-nominal improvement when you crank GB up, but memory all by itself can’t give you performance miracles.
The improvements you see in that chart for games (somewhat over 10% compared to equivalent single DDR platforms) is the most you can expect perform-wise from dual over single DDR.
The review article pointed out that the maximum memory speed in a dual DDR configuration is a good deal lower than in a single DDR configuration. This is not surprising; I actually think it’s doing pretty good for a first-generation product.
What happens in true dual-channel systems is that the memory controller has to make two memory chips work in sync with each other. That’s inherently a good deal more difficult than getting one to do a task.
Imagine that you want to play a trumpet piece. What’s harder to do, having one guy play it, or having two trumpeters playing alternate notes. Dual DDR is like the latter.
What’s important to realize is that two sticks running at 180MHz gets you more throughput than one stick running at 220MHz.
A Matter of Expectations
The introduction of Granite Bay and dual DDR is much like the introduction of DDR and single DDR. In and of itself, it doesn’t get you a whole lot, but thinking that it would was unrealistic.
The board does what reasonably could have been expected from it. It gives you the same kind RDRAM does, essentially because it does the same thing to the same extent as RDRAM. Overclocked, it does somewhat more.
So this is no means a failure.
Whether you want to buy it or not is an entirely different matter.
Many people, especially those who already have a fairly current PIV board, may not think paying a premium price for this board plus two sticks of high speed DDR is worth the boost you’ll get. If bang for the buck is important to you, this is quite understandable and reasonable.
Nor is it unreasonable to thinking one might be better off financially and perhaps technically if one waits for Canterwood and its 200MHz FSB (though I have to have wonder if Canterwood is going to end up be a bleeding edge product simply because DDR is pushing the envelope now).
I suspect that Granite Bay is going to fill a niche similiar to that AMD760 chipset once held over on the socket A side. It may not be the fastest of the bunch six months from now, but it will likely be less skittish than its quicker successors.