Tyan Thunder K7X

[KingofFah]

I haven't bought the board yet, but I was wondering a little about PCI I/O. The S2468 (Tyan Thunder MPX) has a 64bit/66 pci cpu bus. Adds to 533mbs of band for the dual MP's. I was wondering if I put a raid ata133 controller card in the slot will it take away from the bandwidth? Also, the card is backwards compatible to 33bit/33. If I put it in one of the 3 32bit/33 PCI slots, would it affect the CPU bus. Basically the main question is IF I leave the 64/66 slot alone and fill the other PCI slots up with max 133mbs of band being eaten does it affect the 64/66 cpu bus? Are all the pci slots connected in a way that they have a max bandwidth of 533 on all the slots? Is it like 3 33bit/33 pci slots each having 133mbs of band and two 64/66 pci, one of them being the cpu bus, having 533 each? Really need some help here before I buy all the parts. Thanks in advance.

 

[tsapiano]

IIRC the 760MPX chipset uses the 66/64 PCI bus (528MB/sec theoretical bandwidth) to connect the northbridge to the southbridge, as well as service the two 64/66 slots. The southbridge then bridges in a second 32/33 PCI bus.

So, if you completely saturate the 32/33 bus (133MB/sec), you will be left with 363MB/s of theoretical bandwidth for the two 64/66 slots. The problem is that if you put a 33MHz card (either 32-bit or 64-bit) in one of the 64/66 slots, the primary PCI bus is slowed to half speed (266MB/s) and the northbridge-southbridge connection is also slowed, however if you aren't using any 66MHz cards anyway, it shouldn't be a major issue.

It depends on what type of RAID card you are using - if it supports 64-bit/66MHz PCI, then it is definately best to put it in one of the 64/66 slots - as that is the only way to get the full 528MB/sec potential. If it's a 64-bit/33MHz card then your choice is a little more complicated, installing it into a 64/66 will drag down the main PCI busses bandwidth - however installing it in the 32/33 slots will limit its access to bandwidth. It also means that you might end up saturating the smaller bus for other simple PCI devices.

Hope this helps ;

 

[KingofFah]

Thanks for the info tsapiano.

I doubt what I will be using the dual CPUs for will be very HDD bandwidth consuming, so should I just use the ata100 onboard controller and a 7200 ata100 HDD? What I will be doing would eat up memory and completely use the dual cpus, since it is designed to utilize multiple threading. How much of an increase of system performance comes from having that 33 extra? I know the answer will probably be "Depends on what type of things you will be doing". Take the fact that what I will be doing is mostly RAM and CPU intense. Since I also like to game sometimes, how much would that 33 extra affect the gameplay (if any)? The system would already have the GF4Ti4600 and the audigy in it.