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
Final Words
After benchmarking the K8T800 PRO, all we can say is, "IT'S ABOUT TIME!" VIA has resisted adding AGP lock capabilities to their chipsets for a very long time, and it is a real pleasure finally to evaluate a VIA chipset without having to say, "It's fast, but..."Our brief testing showed a working AGP lock on the K8T800 PRO chipset, but VIA and manufacturers do need to get more voltage to the chipset if the lock is to be truly useful. The other unanswered question is the ultimate overclockablity of the K8T800 PRO. It won't be enough just to have check-list features when we have already seen nVidia boards that can reach 300-347 FSB with lower multipliers. VIA also has a working PCI/AGP lock on the new PT880 chipset for Intel, but that chipset still suffers from mediocre overclocking abilities compared to Intel's 865/875 chipsets. Let's hope that VIA doesn't make the same mistake on their flagship K8T800 PRO chipset.
There is no doubt that these are turning into exciting times for Athlon 64 enthusiasts. The processors that we have seen recently have more headroom, 1000 HyperTransport allows much higher FSB overclocks to be reached, .09 process chips should arrive this year, and the unlocked multipliers (down on Athlon 64 and a complete unlock on FX) allow for the kind of memory tweaking that you just cannot do with fixed multipliers, as we see on Intel's Pentium 4 family.
Next month will see the long-awaited introduction of Socket 939, bringing Dual-Channel unbuffered memory to Athlon 64. While they are wearing other clothes right now, we have already seen the two major chipsets for that new socket. The nVidia nForce3-250 and the K8T800 PRO are both very competent chipsets with very comparable features. We really won't know how far either of these chips will go in the new socket until next month. For now, we have unanswered questions with both chipsets. VIA has performed better historically in the high-end Dual-Channel configuration. K8T800 PRO continues that history of performance, but there will have to be improvements in overclocking capabilities for VIA to win this round - at least based on what we are seeing in this Reference Board.
On the other hand, we have yet to see what nVidia will do with Dual-Channel, HyperTransport, and the nForce3-250Gb. The performance on Socket 754 is impressive with excellent overclocking capabilities on the better production boards, but nVidia is still apparently binning chips, since they are offering 800HT to Socket 754 and reserving 1000HT for the new 939 boards. VIA, on the other hand, is moving their entire chipset line to 1000HT, and their yields must be excellent, since pricing for the PRO is the same as the earlier K8T800.
These questions will all be answered soon enough, and we are really looking forward to digging deeper to find answers for you over the next few weeks.
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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.