CHANGE said:
That's an interesting fact. Where then is the current bottleneck in
gaming?
I didn't see the first post, so I'll make general comments here.
PCI express does for PCI what SATA did for ATA (IDE), and what USB did for
serial (RS232) ports.
It's a high speed serial link based on a differential pair.
AGP is effectively an entire PCI bus with one slot on it to improve
bandwidth for the video card. The PCI bus can be easily saturated with a
PCI gigabit Ethernet controller, or a PCI RAID controller (probably 3 disks
required though, really).
PCI-Express just takes that further... whereas PCI has limits and AGP will
find limits at some point, PCI-E will hopefully get rid of the two slightly
different technologies, combining them into one and allowing much greater
headroom without keep breaking compatibility like the various AGP standards
have done.
Since it's a serial technology, not a parallel one, board layout is much
simplified and will hopefully aid the transition to the BTX form factor.
Thats my basic understanding of it, anyway.
In light of PCI-E, PCI-X will be a waste of space. It's like a DDR PCI bus.
It's a temporary stop-gap, it's only saving grace is that it's completely
backwards compatible with PCI. However, there are already too many bloody
standards and technologies. If PCI-X never gets to consumer boards it'll be
a good thing, as it means that PCI-E uptake will be quicker.
PCI-Express is somewhat compatible with PCI, the physical layer is obviously
different, so expect to see adaptors for existing PCI cards to PCI-express,
although this could easily be done on the motherboard - this is where PCI-X
could be used.
I can imagine a system where you have the parallel link from the chipset out
to the first slot (PCI-E 8x) then the second slot (maybe PCI-E 4x) then
maybe a couple of PCI-E 1x slots and then a bridge chip taking it out to a
parallel interface and whack a couple of PCI-X slots in for backwards
compatibility. That would be the best solution all round for a new gen
motherboard.
The general shift from parallel to serial technologies for peripherals is a
good thing. If you look closely at motherboards you will see that it's an
absolute nightmare trying to route all the bloody lanes! Hypertransport,
USB, SATA, PCI-Espress and other (serial, differential pair) technologies,
should, in theory make boards cheaper and easier to produce... and since
it's all so much easier to route, the BTX form factor allows a much more
sensible case layout as well.
Cool, that was the first time I'd thought about the standards in any detail,
so I guess I learnt (or made up) a lot
There's a lot happening at the moment. It should all be for the better.
Current bottleneck in gaming? Maybe CPU, maybe memory bandwidth, probably
GPU - depending on the game. You tend to find that the various buses and
other transmission systems get upgraded before they get saturated. PCI was
a bit late really.
Ben