VOGONS


First post, by brian105

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I currently have a K6-2 450 AHX in my Compaq Presario, which I am planning to OC to 500. However, I know that upgrading the CPU will net bigger improvements, but don't know which CPU to upgrade to. I know the K6-2+ and 3+ are the best contenders, but I'm not sure whether the 3+ is much better than the 2+.
There are some issues though: one, I'm not sure whether the new CPUs will be supported on the current BIOS (which is obviously OEM stuff). I know at a minimum that the K6-3 is supported, since a BIOS update mentions bug fixes about L3, but never addresses which CPUs it adds support for (except a k6-2 475???). I'm hoping maybe somebody here had a model of Presario similar to the 5284 with an MVP3 board which knows about possible upgrades.
Second, the prices on eBay are currently ridiculous. $40 for a K6-3+ 450 seems like a bit too much, and I'm hoping that these inflated prices are due to the pandemic and that they're usually much better (someone correct me if I'm wrong).
I'm hoping somebody has info on these things, and can also advise on which CPU is better to get. Maybe a K6-2+ 550 or 570, or K6-3+ 450? There seems to be a rare K6-3E+ clocked at 550 which I've never seen. Honestly, no idea.

I cut my finger on a modem, don't judge

Reply 1 of 19, by flupke11

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First question you should ask is whether the upgrade is necessary in terms of performance.

If your current system struggles with games that are a tad too heavy, a change in a few MHz might not make much of a difference. Apart from that, another upgrade might make more sense (faster disk, GPU or more ram).

If that's not the issue, and you want to max out the system, just because you can, please disregard the above. Both reasons are just as valid 😀

Reply 3 of 19, by ShovelKnight

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First you have to check if the motherboard supports required voltage (2.0V) for K6+ CPUs.

In my own benchmarks I found that the difference between K6-3+ and K6-2+ at the same clock speed is not huge, but it’s there. It was less than 2fps in DOS Quake at 640x480 (29.8 vs 31.5). There was a somewhat bigger difference in Doom
but both CPUs still run it at over 100 fps.

Reply 4 of 19, by brian105

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The board supports 2.0V until 3.5V, so technically it should work, provided BIOS won't lock me out. If the BIOS does, is there anything I can do to bypass that?

I cut my finger on a modem, don't judge

Reply 7 of 19, by dionb

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brian105 wrote on 2020-05-08, 18:27:

What's the performance difference between a K6-2+ and a K6-3?

As I recall, K6-3 and K6-3+ performed identically at the same speed, the + could just be clocked a lot higher. So clock-for-clock the 2+ will be slightly slower than 3, but the 3 tops out at 450MHz, where the 2+ was officially sold to 550MHz, can easily be clocked to 600+ MHz. Even at stock 550MHz, a 2+ will blow a 3 at 450MHz away.

Reply 9 of 19, by kolderman

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brian105 wrote on 2020-05-08, 20:09:

So in short, I should look for a K6-2+ 450 or higher, and a K6-3 if the BIOS hates that. Got it, thanks!

No, if you were getting a K6-2+ 450 you might as well just get a K6-3+ 450. It's only if you want something faster than that that you might want to look at the K6-2+ 550 - but they are expensive as hell as they are the widest ranging CPU one can buy.

Reply 10 of 19, by frudi

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Except the K6-3+ is even harder to find and more expensive than the K6-2+. And the 450s will most likely be able to run at 550 MHz without issues anyway. So basically just get whatever K6+ chip you can find for a reasonable price.

Reply 11 of 19, by dionb

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As for which is the most expensive out of K6-3, K6-2+ and K6-3+, it really depends on who's selling what when you're looking.

I was able to get a K6-3+ 500 very cheap 2 years ago when someone in Germany was selling a batch of them for EUR 15 each. A year later I picked up a K6-2+ from China for a similar price. I've been hunting for an old K6-3 just to compare - but as I don't actually *need* it I'm not prepared to pay more. No luck - but I haven't really put much effort into it either. For me the + was cheaper than the non+!

They are common enough, particularly in Asia, so with patience and dilligence you should be able to pick up something affordable. But if you want it NOW and shipped from nearby, yes, then it could get pricey.

Reply 12 of 19, by meljor

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@dion I'll send you a k6-3. I have a couple with bend pins that I don't want to put time in anytime soon and I have all the s7 cpu's I need in working condition. The pins will take you ten minutes, you know the drill.... Not at home before monday and don't know the speed but it will be 400mhz or 450mhz.

Don't think I have the adress still so please pm, it will be going your way the coming week. A small gift since you helped me getting the sp98 board and I also like your little tests/projects and input here.

asus tx97-e, 233mmx, voodoo1, s3 virge ,sb16
asus p5a, k6-3+ @ 550mhz, voodoo2 12mb sli, gf2 gts, awe32
asus p3b-f, p3-700, voodoo3 3500TV agp, awe64
asus tusl2-c, p3-S 1,4ghz, voodoo5 5500, live!
asus a7n8x DL, barton cpu, 6800ultra, Voodoo3 pci, audigy1

Reply 13 of 19, by frudi

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dionb wrote on 2020-05-09, 14:26:

As for which is the most expensive out of K6-3, K6-2+ and K6-3+, it really depends on who's selling what when you're looking.

I was able to get a K6-3+ 500 very cheap 2 years ago when someone in Germany was selling a batch of them for EUR 15 each. A year later I picked up a K6-2+ from China for a similar price. I've been hunting for an old K6-3 just to compare - but as I don't actually *need* it I'm not prepared to pay more. No luck - but I haven't really put much effort into it either. For me the + was cheaper than the non+!

They are common enough, particularly in Asia, so with patience and dilligence you should be able to pick up something affordable. But if you want it NOW and shipped from nearby, yes, then it could get pricey.

I was lucky to find a regular K6-3 400, along with a working Asus P5A-B it was installed in, for pocket change at my local flee market. And I've managed to get a pair of K6-2+ chips from exactly the occasional ebay listings from China or Korea that you mention. But I haven't seen a single K6-3+ listed for under 100€ in what must be at least a year now. And it's not for my lack of looking either. I've seen rare US listings for better prices, but then shipping and import duties alone easily add up to 50, 60€.

That's why I'd recommend OP to just get any K6-2+ they can find for a decent price. Especially if they're from the US, as there's usually listings available there all the time for $20-30. The 5% extra performance that a K6-3+ would give really isn't worth waiting who knows how long for one to show up 😀

Reply 16 of 19, by CoffeeOne

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brian105 wrote on 2020-05-10, 03:57:

How high can I raise the voltage when overclocking? I tried 2.5V and it throws VXD errors at me in Windows with a 5.0 * 100 config.

The K6-2 450 AHX most likely can't be overclocked. It's kind of factory overclocked already with the 2.4V, because normally the K6-2 run with 2.2V only.

Reply 17 of 19, by AlessandroB

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CoffeeOne wrote on 2020-05-10, 09:40:
brian105 wrote on 2020-05-10, 03:57:

How high can I raise the voltage when overclocking? I tried 2.5V and it throws VXD errors at me in Windows with a 5.0 * 100 config.

The K6-2 450 AHX most likely can't be overclocked. It's kind of factory overclocked already with the 2.4V, because normally the K6-2 run with 2.2V only.

mine goes quietly to 500, I have not tried to go up but it is not blocked

Reply 18 of 19, by brian105

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It's not a 2.0 V CPU afaik, it states 2.4V on the IHS and runs at 2.4V by default. I'll try up to 2.7V just to make sure I don't melt the probably not good enough cooling.

I cut my finger on a modem, don't judge

Reply 19 of 19, by brian105

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Bad news I guess, I can't really get a stable OC. At 5*100 and 2.6V, there's VXD errors in Windows, and I'm missing another jumper plastic thing to get 2.7V. 2.8V doesn't even try booting so that's out of the question. I thought of possibly doing 5*95, but again I need another jumper thingy which I don't have. So at this point, I'll assume that I need to get another CPU for more performance.

EDIT: Got 95*5 @ 2.4 working successfully, but in 3Dmark I see basically the same performance (within margin of error) possibly because RAM and the AGP iGPU are slightly slower.

I cut my finger on a modem, don't judge