VIA K8T800 PRO: PCI/AGP Lock and 1000 HyperTransport for Athlon 64
by Wesley Fink on May 6, 2004 5:00 AM EST- Posted in
- CPUs
BIOS Features: VIA K8T800 PRO Reference Board
VIA used the familiar Phoenix-Award BIOS on the K8T800 PRO. We have seen award on most VIA boards, and navigation will be familiar for most users.
Reference Boards rarely have the kinds of adjustments for FSB and voltages that uses demand on shipping boards. There are no voltage controls at all on the K8T800 PRO. There is at least a Frequency and Voltage Control sub-menu, though the options are pretty minimal.
PCI/AGP lock is one of the major new features of the PRO chipset, so VIA did include some basic FSB controls to test the lock. FSB can be adjusted to 255, a very low figure compared to the 300MHz and higher that we are seeing on nVidia nF3-250 boards. It's rather short-sighted of VIA's engineers to include rather average FSB adjustments and no CPU or memory voltage adjustment at all. This made testing the new lock harder than it needed to be.
The ability to "lock" AGP/PCI is called "Asynch AGP Clock Control" in the VIA BIOS. While the Reference Board only offers a couple of lock frequencies, VIA says the BIOS will be set up by some manufacturers with a wide range of lock frequencies. While that always looks good on paper, the ability to lock at standard 66/33 is what matters most to overclockers.
The other major addition to the PRO chipset is 1000 HyperTransport, which can be selected in the LDT menu.
HyperTransport at 1GHz is part of the new 939 specification, but as we saw in our review of the MSI K8N Neo, the availability of 1GHz can certainly open options for the overclocker.
It was good to see a decent selection of memory timings on the K8T800 PRO board. This allowed the Registered memory to run at its best timings so that performance could be better compared to other Socket 940 motherboards.
Basic Features: VIA K8T800 PRO Reference Board
Overclocking and Stress Testing: VIA K8T800 PRO Reference Board
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Odeen - Saturday, May 8, 2004 - link
#4: The answer is pretty much a "yes"Reason: Firewire, in this design, sits on the PCI bus. Gigabit networking sits on the PCI bus. Any soundcard / chip better than chipset-provided onboard sound sits on the PCI bus. Any additional hard drive controllers sit on the PCI bus.
On non-server motherboards, the PCI bus runs at 33mhz and is 32 bits wide, for 133 megabytes/sec of bandwidth
Firewire is 400mbit/sec per port. The new design is 800mbit/sec. This means you will use a maximum of 50 megabytes/sec for a firewire/400 port (granted, the practical peak is less than 50mb/sec, but you'll never eke out 133mb/sec out of the PCI bus either). Add to that the 250mb/sec full-duplex Gigabit Ethernet can generate, and 150mb/sec for ever SATA port courtesy of those Silicon Image chips, and you can see that you're starved for bandwidth.
On the other hand, there's a tidy 533 megabytes/sec of bandwidth between the northbridge and the southbridge.. that means everything that runs straight off the southbridge can report back to the northbridge and, consequently, to the CPU at 533mb/sec. Subtract 133mb/sec for the PCI, and you still have 400 megabytes for LAN and hard drives and firewire, if it's implemented in the southbridge.
Unfortunately, the only true "onboard" firewire comes courtesy of the MCP-T southbridge on nForce2 boards. Everyone else (All Via, all SiS, all Intel chipsets, and all chipsets for Athlon64) has to use a PCI firewire chip.
Pumpkinierre - Friday, May 7, 2004 - link
Welsey #11, I would liked to have seen an 8or9 x 233and234. I still smell a rat. I've run some mobos at 41MHz PCI speed in the past while others (same brand and chipset but different review) would not function. The fact that other posts claim that ABIT have left out the AGP/PCI lock feature of this chipset adds to my suspicion.Klaasman - Friday, May 7, 2004 - link
Why oh why ABIT, would they leave this out?? Damn it!blup - Friday, May 7, 2004 - link
This board breaks my heart. I was hoping for a "BH7 for Athlon 64" i.e. cheap, fast, very overclockable. It is not to be.ABIT has NOT implemented the PCI/AGP lock on this board - maybe there will be a more expensive MAX model that does. Checkout one man's review at http://www.nickgoodall.org/kv8pro/review1.htm
Wesley Fink - Friday, May 7, 2004 - link
#10 -I did a quick check with PC Geiger and the bus was locked on the Reference Board. Since I had the board for only 2 days for testing, there was no time for much more. You will also see I reached 231 overclock on the FX51 at 10 ratio, in addition to the 255x8.
Checking my review notes, I also tested the 10 multiplier at 233 and 234 to determine if there was a ratio drop. I could boot at 233 but the system wasn't completely stable; the CPU simply would not do 234 at standard multiplier. This also suggests a working lock.
Please also keep in mind that VIA has a working pci/agp lock on the PT880 chipset for the P4, so this is not their first PCI/AGP lock. It is just their first lock on an Athlon 64 chipset.
Pumpkinierre - Thursday, May 6, 2004 - link
You got to 8x252 on the Aopen AK86-L (VIA chipset/Skt754) which didnt have PCI/AGP lock but ratio controlled. Given its an a64/FX chipset (and on top VIA) where AGP/PCI lock has been a matter of controversy, would'nt it have been prudent to have used your PCIgeiger to check the PCI frequencies at the different FSB settings-so that we wont be fooled once again!Jeff7181 - Thursday, May 6, 2004 - link
This is definately a good thing... finally overclockers have a choice between chipsets.Warder45 - Thursday, May 6, 2004 - link
I thought the Pro was going to have a HT speed of 1200?Wesley Fink - Thursday, May 6, 2004 - link
#6 -PCI/AGP lock is DEFINITELY working on the Reference Board, but I can not yet address whether Abit has implemented the lock or just dropped the PRO chipset in the older design with no changes. I did see the one review in the UK reporting this issue before the VIA review was finished.
We do have the Abit board coming to us for testing and I will report what I find.
Klaasman - Thursday, May 6, 2004 - link
Abit has a board out now but reports are that it does NOT have the AGP/PCI lock working.