K6-2+ 550MHz or K6-III+ 500MHz, is cache or frequency more important?

After my last post comparing the K6-2+ and K6-III+ cores at the same 500MHz frequency, I wondered if it is better to run a K6-III+ 500 or a K6-2+ 550 MHz in my system to obtain the maximum performance. So the basic idea is to know if gaining 50MHz is better than gaining 128KB of L2 cache.

So here are my 2 contenders as seen by CPU-Z. The K6-2+ is probably the easiest chip to find if you build a retro-K6 system.

And here are the scores from 3DMark 2001 SE. Before the test I was sure the 50MHz increase would be the dominant factor, as it represents a 10% increase. From the previous test we knew that the 128KB increase at a fixed 500MHz speed yielded a 6% performance increase.

Surprisingly, the K6-2+ obtained a score of 2001 and the K6-III+ a score of 2016! So the cache increase actually outweights (slightly) the frequency gain. In practice I doubt that you will feel any difference, so if you have one chip or the other and wonder if you should upgrade, just stay with the one you already have :)

K6-2+ or K6-III+ at 500MHz, which is better?

I have quite a bunch of AMD Socket 7 CPUs around, from the humble K5 to the latest K6-III+ versions produced. So yesterday I made a little test with 2 CPUs I clocked at 500MHz to compare the 3DMark 2001 SE results on my system.

The first contender is a K6-2+ 500 (really a 550 downclocked), which is the low-power (0.18 micron, 2.0V) variant of the K6-III core with only 128KB L2 cache as you can see on the CPU-Z screenshot.

The second chip is a K6-III+ 500, which is the same chip but with the full 256KB of L2 cache, this one runs at an even lower 1.8V.

Running 3DMark 2001 SE gives us 1900 points on the K6-2+ and 2016 points on the K6-III+, which is a 6% increase only die to the aditionnal 128KB of L2 cache. This is of course only one benchmark which also takes into account graphics, but it gives us a good idea of the performance increase between the 2 “high end” cores produced at the end of the K6 family life.

K6-2 CPU performance reduced by 50% because of USB 2 card

Recently I found that my K6 system was running slow in some games, the mouse was for example lagging and games like C&C Red Alert were unexpectedly slow. So I ran a 3DMark 2001 benchmark with the default setting and got this, 1312 points. This is not normal for such a system.

One change I recently made was to add an USB-2 PCI card (NEC chipset) to my system so I can use faster USB keys to transfer data around. Could it be the problem? I went to the device manager and disabled the card under Windows XP. After a reboot I ran the benchmark again…1990 points this time. This is a huge difference.

Going even further, I physically removed the card and ran the benchmark once again, this time 2011 points! That’s around 55% increase in performance and it was all due to the USB 2 controller, even when nothing was connected to it.

So beware if you add hardware to your system…All the benchmarks were run 2 times and the results were close, so it’s not a fluke. And my system feels responsive again.

Activate Windows XP in 2022

If you install a fresh copy of Windows XP in 2022, you will probably notice that the automatic activation process fails. This is because Microsoft retired this service, after all the OS is more than 20 years old and it is not able to connect to most SSL sites anymore.

But do you know that Windows XP can still be activated? For that, start the activation wizard and try to activate Windows online: it will fail.

Then select “Activate by Phone” and follow the guided messages, you will be asked for a series of numbers like the ones displayed on the screenshot below.

Once you get you activation code, bingo, it works!

Windows 7 (and XP) on my AMD K6-2, some notes

Yesterday I finally tried an upgrade path from Windows 2000 to Windows XP to Windows 7 on my AMD K6-2+ 550 system. As it may be of interest to some other people, here are some notes about the process:

  • Upgrading from Windows 2000 to Windows XP SP3 went totally smoothly, all my hardware still had functioning drivers after the upgrade process. The OS itself feels a bit slower than Windows 2000 but some programs that did not run on 2000 now work on XP. The only problem in 2022 is that you can’t (easily) activate Windows XP nor do any Windows Updates as the feature has been discontinued by Microsoft.
  • Upgrading from Windows XP to Windows 7 also went well, I started the installer in the evening and the next morning my Windows 7 desktop was ready. Now for the bad part…the OS feels globally very sluggish. It perfectly works, you can run modern software (as long as it doesn’t need SSE) but the user experience is not enjoyable. And the biggest problem is the support of legacy hardware. On my system, my Sound Blaster 128 an my 3Com 3C905 NIC are not recognised anymore and no drivers exist for Windows 7.

So the bottom line is: yes, Windows 7 will absolutely run using around 400MB of RAM after boot, but the big issue is the unsupported hardware coming from Windows XP where everything works. This is no real wonder, the hardware and XP are “period matching”. Windows 7 on the other hand was released in 2009, 10 years later.