nForce3-250Gb: WORKING AGP/PCI Lock

It should not be a surprise that the first thing we confirmed is a working PCI/AGP lock. After discovering that none of the previous Athlon 64 chipsets had a working AGP lock, we went immediately to a test to verify that the AGP lock was indeed working. We used PC Geiger that was used for measuring PCI in PCI Speed and Overclocking: A Closer Look at A64 and P4 Chipsets. With FSB set at 249 and AGP frequency set to 67, we measured a PCI speed of 33.3MHz.

This is the expected results for a working AGP lock. We certainly can confirm that the AGP lock is working on the nForce3-250GB Reference Board, and we'll take another look when shipping nF3-250 boards start showing up in a couple of weeks.

FSB Overclocking Results

Reference Boards are not really designed for overclocking, and there are normally not any voltage adjustments available as we would see on production motherboards. However, with PCI/AGP lock available, we were anxious to see if the nForce3-250Gb did indeed overclock better. This was also an opportunity to verify a working PCI/AGP lock by a different method.

Front Side Bus Overclocking Testbed
Default Voltage
Processor: Athlon 64 3400+
CPU Voltage: 1.5V (default)
Cooling: AMD Stock Athlon 64 Heatsink/Fan
Power Supply: Powmax 350W
Maximum OC: 2442MHz (+11%)@222x12
2375Mhz@250FSBx9.5 (+25% FSB)

The above overclocking setup at default voltage allowed us to reach a stable Frequency of 250 at 800 HyperTransport with AGP/PCI fixed at 33/66. The limit of this CPU at default voltage is apparently somewhere around 2450MHz, since we could not reach 250FSB with a 10 multiplier. That would have represented 2.5GHz, had we been successful.

Important here is the fact that we reached the absolute highest FSB setting of the Reference Board, which is 250. This is further evidence that the AGP lock is indeed working on nforce3-250.

We asked nVidia about the issues with the nForce3-150 AGP/PCI lock, which are apparently fixed in nF3-250. nVidia assured us that the AGP lock was indeed working in the 150 Reference Board, but that the BIOS implementations by manufacturers with the 150 chipset were not correct. Therefore, the shipping boards for nF3-150 did not have a consistently working AGP lock. nVidia also assured us that they were working more closely with manufacturers on the nF3-250 launch to make sure manufacturers were delivering nF3-250 boards with working AGP lock.

We tested nVidia's claim and found the Reference nF3-150 board did have a working AGP lock. The AGP lock is also definitely working on the 250 Reference Board, and we sincerely hope we will find the same working lock on shipping nF3-250 motherboards. We will be looking closely at production nF3-250 boards to verify a working AGP lock.

Reference Boards are rarely a good indication of the true overclocking abilities of a chipset because they are designed to qualify and demonstrate a chipset at design parameters. The features are definitely here for the best overclocking in current Athlon 64 chipsets. It is also worth mentioning that the Athlon 64 Multiplier Utility, available as shareware from CPU-Z, worked fine on the nForce3-250. While it was designed for the 150 chipset, nVidia saw no reason why it should not work properly and we did confirm that the multiplier adjust utility works.

nForce3-250Gb Reference Board: Basic Features nForce3-250Gb: On-Chip Gigabit LAN


View All Comments

  • Curt Oien - Tuesday, March 23, 2004 - link

    PCI EXPRESS ? Reply
  • prisoner881 - Tuesday, March 23, 2004 - link

    There's a huge gaffe on the On-Chip Gigabit page. It states that Fast Ethernet runs at "100MB/sec" and Gigabit runs at "1000MB/sec." "MB" is shorthand for mega<i>bytes</i>, not mega<i>bits</i>. Megabits should be abbreviated "Mb."

    Normally I wouldn't be this anally-retentive, but the poor usage leads to another problem later on down the page. The article states that Gigabit Ethernet running at "1000MB/sec" is faster than the PCI bus which runs at "133MB/sec." The PCI rate figure is correct, but the Gigabit figure makes it look like Gigabit is about 8 times faster than the PCI bus itself. <i>It's not!</i> The PCI bus runs at (133Mbytes/sec X 8 bits/byte = ) 1064Mbit/sec, which faster than Gigabit. The article is very misleading in this respect.

    In truth, the PCI bus can almost never reach its peak 133MB/sec rate (usually it's around 100MB/sec) but then again Gigabit can't reach it's peak either.

    Regardless, the article is completely incorrect when it indicates a Gigabit card would overwhelm a PCI bus. This is not true.
  • BikeDude - Tuesday, March 23, 2004 - link

    Argh... I keep forgetting that it's 1000Mbps _full duplex_... nVidia are indeed correct, the PCI bus is only half that speed. :-/

  • BikeDude - Tuesday, March 23, 2004 - link

    First off: GB is GigaByte. Wesley wrote "GB" more than once while actually referring to Gigabit (bit has lowercase b).

    Next, 1000Mbps is roughly 125MB/s (theoretical peak I expect). 33MHz 32-bit PCI is roughly 133MB/s. I dislike PCI Gb implementations as the next guy, but I'd still like to know how nVidia managed to come up with the half speed figure? Perhaps nVidia's PCI-bus implementation is sub-par? (which is a real issue! Via has struggled with really bad PCI performance for years :-( )

    Finally there's 6-channel audio; What happened with Soundstorm and Dolby encoding implemented in hardware? (I currently use only the SPDIF connectors on my nForce2 and get surround sound both in games and while playing DVDs -- is there no way to get this functionality with Athlon64?)

    Hopefully the next article will shed some light on some of these issues. Cheers! :)

  • KristopherKubicki - Tuesday, March 23, 2004 - link

    gigE is awesome and worth it. i dunno about the firewall but eh. 45MB/s network transfers are fun.

  • Verdant - Tuesday, March 23, 2004 - link

    schweet... when is my 16x nforce 250 mobo comming the the mail? Reply
  • klah - Tuesday, March 23, 2004 - link

    hmmm.. seems that last page was slipped in from the November SiS article. weird.

  • Phiro - Tuesday, March 23, 2004 - link

    yeah, the SiS 755FX plug at the end was sort of a red-herring - didn't fit at all with the article, which was soley about Nvidia, it didn't need SiS's recent efforts tacked on the end at the last second.

    A couple things:

    1) to all you nay-sayers about the worth of gigabit ethernet - I thumb my nose at you! Let's not play chicken or the egg games here, let's just usher in new *desired* technology as smoothly as possible - having gigabit ethernet will push me to replace my netgear 10/100 switched hub, not the other way around.

    2) Anandtech, what's with the nvidia ass kissing? When you say things like 'Nvidia assured us.." and "We did test Nvidia's claim... [and we believe it]" - come on, a little healthy doubt is a good thing. Just because they supplied you with a reference nforce3 250 mobo doesn't mean you have to see how far you can stick your tongue up their butt. Honestly, the article felt like it leaned toward Nvidia abit. Believe it or not, you can report on a product without it sounding like some money changes hands or something.
  • mechBgon - Tuesday, March 23, 2004 - link

    *drool* Reply
  • bldkc - Tuesday, March 23, 2004 - link

    What's with the SiS 755 crap at the end of the article? Someone didn't proof read, huh? That is also obvious in the spelling errors. Excellent article. Better than recent ones. I do wish that you had been able to include the performance portion, cuz now I'm itching to see them.
    One thing tho, how many people have several gigabit systems at home? I know I will not upgrade any of mine until they are replaced, so it will be awhile. Therefore I am not too excited at this point, especially if the high speed wireless standards work out to high enough throughput to allow real time multi-media transfers. Love the on chip firewall, but Zonealarm is still the only useful application specific solution I know of. Not that I'm an expert, I am far from it, but the Blackice debacle was seen coming long ago.

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