# This is at least amusing …

So we had the little … I dunno what to call it … fiasco, mebbe? where we were promised a reasonable comparison between a JackRabbit and a Thumper, and did not get it (a reasonable out-of-box comparison, no one I know who promises accurate comparison purposefully de-tunes one platform before comparing). I am not going to dive back into that mess. When we are paid to benchmark, or when we do it on our own, we never, ever start out by ignoring the vendor/authors on what makes it slow/fast. We ask them how to get the best performance, and we do a baseline measurement out of the box. Even more to the point, we take great pains to try to get the maximum performance of each box after baselining it.

But that is another discussion. Might be worth suggesting to SC07 in terms of a benchmarking technique tutorial.
Ok. Back to the topic.
One of the points we make in our white paper for JackRabbit, is that with 4 x PCIe (2 PCI-e x8, 2 PCI-e x16), we have quite a few lanes of PCI-e IO bandwidth available. 48 lanes to be precise. At 0.5 GB/s per lane, this gives us 24 GB/s sustained IO/bandwidth. Unfortunately, the vast majority of motherboard designs tie the PCIe channels to one processor. Saves them design money, allows their units to be used with a single processor. But it limits your performance to the HT performance. Still, this is on the order of 10 GB/s, so it is not terrible. But most IO is implemented in terms of memory to controller DMA, so you are memory bandwidth bound, so lets call it 6 GB/s as a “realistic” limit on most current motherboards. You report much above this, and you are likely dealing with a huge cache memory somewhere.
So I read a report on a “do it yourself X4500” in which the author castigates anyone attempting to replicate the functionality of the Thumper (x4500). Their point is that with 3 independent PCI-x busses, Thumper has bandwidth to spare. Along with lots of other nice bits of engineering.
This is goodness. Several customers have them, and they seem to like them. I have some responses which are sadly non-quotable for two reasons, one being that their company doesn’t allow being quoted (under pain of being fired), and that it has lots of … colorful … language in it. The gist is that JackRabbit is (*&(*$^%$^( fast. Really (*&(*$^%$^( fast.