K6-II 550Mhz vs. K6-III 400Mhz

Discussion relating to Socket 7 hardware.
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KenB
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K6-II 550Mhz vs. K6-III 400Mhz

Post by KenB » Wed Sep 01, 2010 6:09 am

I've got an old school gaming system running nice with a 400 K6-III on it (regular K6-III, not "plus" model). Wow, the thing even plays DVD's pretty smoothly, too, using a 3DFX Voodoo3 card and 100Mhz FSB for the RAM. I was never able to get DVD's to play good on K6 machines before, and I believe I had determined a few years ago that it was because most of the Super Socket 7 chipsets available did not have fast enough memory interface. Although this particular VIA VP3 based-board (FIC 2013 board) seems to do the trick.

Was wondering if a regular 550Mhz chip might perform even a little better? I tried overclocking this III unit, and it won't budge much past 400.

Anyone have idea on that?

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AlleyViper
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Post by AlleyViper » Wed Sep 01, 2010 6:54 pm

I really wouldn't bet on it. If your MB supports, go to a k6 2+ instead if you can't get a III+, both should be quite cheap now.

Depending on your MB cache, a regular K6 2 will slow down your system too much due to it's maximum cacheable memory cap, which can be limited as some measly 128MB* if you only have 512kb L3 onboard. The on-die L3 cache gets rid of that limit.

*edited
Last edited by AlleyViper on Thu Sep 02, 2010 6:19 am, edited 1 time in total.
Shuttle HOT-591P 512KB L3 REV.2.0, bios 591PS025 @100/66/33 1:1
K6-III+ 500 ANZ 256KB L2 @600MHz/2.0V + CM DP5-6I31C-A1, TT 6x2.5cm/7krpm/38cfm fan @7V
2X256MB pc133 CL3 @100MHz/2-2-2-5
HP GeForce2 GTS 32MB AGP
SB AWE64 Value ISA, SiS900 NIC, Trust USB 2.0 5-Port PCI
Samsung Spinpoint 80GB, Quantum Fireball 6.4GB, Yamaha CRW3200E
Mini AT case (ATX modded) with:
8cm TT Std Fan @7V
Generic 300w ATX

KenB
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Post by KenB » Thu Sep 02, 2010 1:48 am

Mmmm. OK, I didn't think about that. However, my board has 1MB L2 built-in. What is the cacheable limit of a system with 1MB?

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AlleyViper
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Post by AlleyViper » Thu Sep 02, 2010 6:19 am

Acording to this post http://www.tomshardware.co.uk/forum/732 ... mhz-advice , it should be 256MB. But still, you should be looking for a cpu with L2 cache instead.
Shuttle HOT-591P 512KB L3 REV.2.0, bios 591PS025 @100/66/33 1:1
K6-III+ 500 ANZ 256KB L2 @600MHz/2.0V + CM DP5-6I31C-A1, TT 6x2.5cm/7krpm/38cfm fan @7V
2X256MB pc133 CL3 @100MHz/2-2-2-5
HP GeForce2 GTS 32MB AGP
SB AWE64 Value ISA, SiS900 NIC, Trust USB 2.0 5-Port PCI
Samsung Spinpoint 80GB, Quantum Fireball 6.4GB, Yamaha CRW3200E
Mini AT case (ATX modded) with:
8cm TT Std Fan @7V
Generic 300w ATX

Jim
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Post by Jim » Thu Sep 02, 2010 8:12 pm

Your best bet, though hard to find is a K6-3+ 550 ACR. Second best is a K6-3+ 500 ANZ. Third best is a K6-3+ 450 ACZ. Any of these is quite capeable of clocking 600 MHz (6x100) or slightly higher, though you will get better memory performance using the 5.5 multiplier (5.5x100 = 550 MHz works better than 6x100 = 600 MHz for some reason.) For best results OC the FSB as high as you can get it to run stable when using the 5.5 multiplier.

See : http://www.k6plus.com/index.php?name=PN ... pic&t=1434
Superpuppy 3
K6-3+ 450 ACZ (6x100)
DFI K6BV3+/66 Rev B2 (2 Meg) w/ 2x28mm Chipset Fans
2x256 Meg PC 133 Hynix SDRAM
1x 20G Maxtor (7200)
2x 80G Maxtor (7200) Ducted w/ 2x486 Fans Mount
52/24/52/16 LG CDR/RW/DVD
8/4/3/12/24/16/32 LG Super Multi
ATI 9000 aiw Radeon AGP
SB Audigy 1 MP3 Sound
CMD 649 IDE Controller
NEC USB 2 Card

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jsc1973
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Post by jsc1973 » Mon Sep 13, 2010 9:58 am

You might get a little better DVD playback with a K6-2 550, because DVD playback on a system without SSE is very FPU-dependent, and a K6-2 550 will beat a K6-III 400 in raw FPU performance. The FPU in the two chips is identical.

However, there are several reasons I wouldn't do this:

1. A K6-III 400 blows the doors off any K6-2, even a 550, in all other respects.

2. A K6-2, because of its antiquated cache design, is almost helpless if used on any of today's software, which expects and depends on a fast L2 cache. A K6-2+ or K6-III, while not fast, will still get the job done.

3. The K6-2 550 had a history of unreliability. It was basically a factory overclock. If I see a K6-2 550, the first thing I do is set it back to 500.

4. For very little money, you can buy a K6-2+ CPU now, overclock it to 600 MHz, and get the performance of a K6-III 550, rather than a K6-2 550.

It doesn't surprise me that you were unable to overclock the original K6-III. Those chips ran at their thermal limits, and AMD never got great yields on it. The rare K6-III 333 was a good overclocker, often good for 112*3.5 on a VA-503+, at which speed it was faster than a P2-400 or Celeron 466. But you didn't see many of those parts.

K6 systems are still viable today, but you almost have to have a K6-III, K6-2+ or K6-III+. The three-level cache is what keeps them able to do useful work. In the last several months, I've revived four old Compaq 1200 and 1600 series laptops by replacing their old K6-2 processors with K6-2+ or K6-III+. Even a model 1273, stuck on a 66 MHz bus, is usable now, thanks to a K6-III+ 450, running at 400 MHz and 1.8v.
FIC VA-503+, Rev. 1.2, AMD K6-III+ 450@550MHz, 80GB Seagate ATA-100, 3dfx Voodoo3 3500 TV, TB Montego II Quadzilla, Win98se, 384MB PC100

Compaq Presario 1273, AMD K6-III+ 450@400MHz 1.8v, 40GB Samsung 5400RPM, extremely hacked Win98SE, 288 (yes, 288!) MB RAM
(Also an AMD FX-8350, which does the heavy lifting these days...)

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