Just what is the HyperTransport bus

[imported_aragorn18]

Ok, with my new AMD system I'm a little confused. I understand that HyperTransport is the point-to-point bus that allows all of the components to talk to each other. What I don't understand are the speeds of all of the pieces. Can someone explain, or point me to an article that explains how FSB speed, RAM speed, HT multiplier and CPU multiplier all relate? Thanks.

 

[Nyati13]

There is no FSB.

How it all relates is....

The CPU is the central hub of everything It has a clock generator circuit that makes the clock ticks for the entire system to run off of. It has a memory controller hitched to one side, that runs the RAM at whatever the set divider dictates. (ie PC3200, PC2700 etc) There is also at least one HT Link hung off the CPU core as well. This runs at whatever speed the HT multiplier dictates (ie 1600MT, 2000MT) . The HT Link is the CPU's connection with everything else in the computer (except the RAM of course). At the other end of the HT Link is the motherboard chipset. This chipset will contain all of the AGP, PCI busses, and all the other stuff in a computer.

The standard A64 skt 939 has a clock generator running at 200MHz. THe CPU will run at whatever the model # is set to. (My A 64 3500+ runs at 2.2GHz). The RAM then divides off of the CPU clock (in mine divide by 11 = 200MHz DDR), and the HT Link runs at the clock generator times a set multiplier. (In mine x5 = 1000MHz / bidirection = 2000MT)

See, clear as mud!!!

 

[Brian23]

Originally posted by: Nyati13

There is no FSB.

How it all relates is....

The CPU is the central hub of everything It has a clock generator circuit that makes the clock ticks for the entire system to run off of. It has a memory controller hitched to one side, that runs the RAM at whatever the set divider dictates. (ie PC3200, PC2700 etc) There is also at least one HT Link hung off the CPU core as well. This runs at whatever speed the HT multiplier dictates (ie 1600MT, 2000MT) . The HT Link is the CPU's connection with everything else in the computer (except the RAM of course). At the other end of the HT Link is the motherboard chipset. This chipset will contain all of the AGP, PCI busses, and all the other stuff in a computer.

The standard A64 skt 939 has a clock generator running at 200MHz. THe CPU will run at whatever the model # is set to. (My A 64 3500+ runs at 2.2GHz). The RAM then divides off of the CPU clock (in mine divide by 11 = 200MHz DDR), and the HT Link runs at the clock generator times a set multiplier. (In mine x5 = 1000MHz / bidirection = 2000MT)

See, clear as mud!!!

:thumbsup:

 

[WildHorse]

To quote aragorn18:
"HyperTransport is the point-to-point bus that allows all of the components to talk to each other"

So this sounds like HT is merely another name for two things taken together, namely DMA & I/O resources.
DMA channels (for communications directly from component-to-component and not involving the cpu) and for I/O channels (for communication sent from the cpu to the other hardware) ??? Sounds like that to me!

 

[miketheidiot]

oin multi processor systems it is the direct channel between CPU's. Basically CPU to CPU without a middlepoint.