K6 Box Part 2 – GA-5AX Capacitors

One thing that will inevitably bite you on old hardware are dead capacitors…they either dry out, explode or leak inevitably regardless of their initial quality after 15 years. On one of my GA-5AX boards I had some instabilities and this is exactly the sign of dried-out capacitors :(

One of you is dead!

So I ordered a bunch of new ones to replace them all, there are 2 types on the motherboard:

  • 8mm diameter 330uF 25V a bit everywhere
  • 10mm diameter 330uF 25V close to the CPU
If you can’t find 25V ones you can take caps rated at 35V instead and it will just work fine.

The removed old caps (the blue ones are from a GeForce 3)

Replacing them all (around 20 pieces) took me a good 2h of careful work…the soldering wasn’t that easy to do and I had to drill trough some of the old soldering with a very small drill bit.

Fitting the first new capacitors…

The new capacitors are also a little bit shorter, 12.5mm height instead of 15mm which is absolutely perfect around the CPU as many heat-sinks will now fit off the shelf without requiring some adjustments. Oh and the board is stable again now :)

New capacitors!

You may have notice the 2 places on the previous picture where capacitors were planned on the motherboard but never fitted? Well meanwhile I soldered some in there and it didn’t change anything…nothing burned :)

Cacheable RAM on Socket 7 platforms

One thing I completely forgot about since I had a Socket 7 system was the whole “Cacheable RAM Size” also called “Cacheable Area” concept.

In short this implied that you could have a motherboard supporting 768MB RAM but only the 256 first MB could be accessed quickly by the CPU and the 512 other MB were slow at the point your system could be slower with 768 MB than 256 MB…so you probably wonder where this limitation comes from and what to chose today to max out the 768 MB you want on your motherboard, right? ;)

First of all you have to remember that in 1998-2000 not that many people even had 256 MB in their systems so this problem didn’t affect many users. But let’s go to the cause of this problem…the “Tag RAM”; it’s a small memory usually located in the chipset which keeps track of where in memory the entries stored in the L2 cache are. So the “Cacheable RAM” one can address is dependent on the Tag RAM size and the chipset design.

For K6 and K6-2 CPUs (not the K6-III and “+” models) the rule to know what RAM size is cacheable is quite “simple”:

 VIA MVP3 with Write Back cache strategy set in BIOS

  • With 512 kB Level 2 Cache, 64 MB are cacheable
  • With 1024 kB Level 2 Cache, 128 MB are cacheable
  • With 2048 kB Level 2 Cache, 256 MB are cacheable

VIA MVP3 with Write Through cache strategy set in BIOS (2-3% slower system)

  • With 512 kB Level 2 Cache, 128 MB are cacheable
  • With 1024 kB Level 2 Cache, 256 MB are cacheable
  • With 2048k B Level 2 Cache, 512 MB are cacheable

ALI Aladdin V revision D and E

  • With 512 kB Level 2 Cache, 128 MB are cacheable
  • With 1024 kB Level 2 Cache, 128 MB are cacheable

ALI Aladdin V revision G

  • With 512 kB Level 2 Cache, 512 MB are cacheable
  • With 1024 kB Level 2 Cache, 4096 MB are cacheable

Just to help you a little bit more, the ALI Aladdin V revision G chips are used by ASUS for the P5A since revision 1.06 and for the P5A-B since revision 1.05. Most of the P5A boards out there are revision 1.04. But how does one actually check for the revision? Well it’s written on the northbridge, it’s the last letter from the line just above “Taiwan”.

ALI Aladdin V

ALI Aladdin V Northbridge – Revision E

Now you are probably thinking you are pretty much screwed as finding an ALI Aladdin V to support your shiny 768 MB RAM isn’t an easy task…well not completely…let me introduce you the K6-2+ and K6-3(+).

With these chips and their onboard L2 cache (256 kB for the K6-III(+) and 128 kB for the K6-2+) all these issues magically disappear and the limit is 4 GB! So just install one of the “+” chips if you can and need RAM…

Now there is another thing to be aware of…due to a hardware design problem, the Asus P5A with the ALI Aladdin V revision G do not support the “+” CPU well at all, in fact they run extremely slow!

So, now you pretty much have all the info needed to maximise your RAM usage!


Today I had to undergo an horrible experience namely find a computer with a diskette drive, a diskette drive for my K6 system and some diskettes. In the K6 days every computer was expected to have a 3.5″ 1.44MB diskette drive so when you had to update your BIOS you had to make a boot diskette with the flash utility and the BIOS on it.

Back of a 3.5″ diskette drive

Even when you install Windows XP and want to provide additional disk drivers it’s only capable of loading them from a diskette…

Front of a 3.5″ diskette drive

Today I was a bit in a stupid chicken and egg situation; I had to update the GA-5AX BIOS so I needed a boot diskette. Unfortunately no PC in my home has a diskette drive nor do I have diskettes…nor do the modern motherboards have a connector to plug a diskette driver on them :)

As I had thrown away all my diskettes years ago being ABSOLUTELY SURE I would never use one again I went to my local computer shop and guess what? Verbatim started to produce some diskettes again due to demand. So here is a brand new 2012 diskette box!

A new diskette box!

Now that I had my diskettes I went to a friend’s home which I knew still had an old PC…he was able to generate a boot diskette for the BIOS update and another diskette with the Promise SATA controller drivers for Windows XP on them. I now had diskettes with the right content on them!

I then went to my local computer shop again and could salvage an old, ugly and dusty diskette drive from a case in the recycle bin…after some cleaning I fitted it to the K6 system and it worked!

Windows XP after loading SATA drivers from the diskette!

K6 Box Part 1 – Hardware

Today I finally received the first batch of parts for my K6 system! The motherboard is a Gigabyte GA-5AX revision 4.1 with the latest F4 BIOS, it is equipped with a K6-III 450 MHz and 3 single-sided 256 MB memory modules which don’t work because the Aladdin V chipset can’t handle them…I will have to order double-sided modules.

Gigabyte GA-5AX rev 4.1

A closer look at the ALI Aladdin V north-bridge, it’s branded with a “100 MHz” printing.

ALI Aladdin V

ALI Aladdin V Northbridge

Then I tried to fit my Just Cooler P-600 Socket 7/A/370 CPU cooler but it didn’t fit due to some capacitors on the GA-5AX; some fins will have to go away…

The cooler does not fit with the capacitors…

…and here is the (ugly) result after 3 minutes of work with my Dremel. It now fits perfectly! I have ordered another better cooler though but it didn’t arrive yet.

A little Dremel later, it fits…

The case I chose for the K6 is a low-cost but still nicely built Thermaltake V4 Black Edition which costs around 35€ without power supply. The interior is nicely black and no sharp edges stand out so for me it fits my needs…the metal is very thin though and it should be placed in a spot where you don’t continuously hit it with your feet.

The power supply is a new ATX 1.3 compatible LC Power LC420H-12 costing around 20€.  It very probably doesn’t deliver the 420W it claims to and the build quality feels minimal…but for a K6 it should not be overloaded and thus provide enough stable power and it’s quiet.

The empty case

The motherboard is now fitted into the case with all the expansion cards:

  • ATI All In Wonder Radeon 8500 64MB RAM by Pinnacle
  • SoundBlaster 64 audio card
  • 3Com 3C905-C 100 Mbits network card
  • Promise SATA-300 TX2 Plus SATA controller
  • 250GB Western Digital Caviar Blue HDD

The motherboard with all its cards

VIA Apollo MVP3 chipset press release

For the sake of keeping it somewhere, here is the VIA Apollo MVP3 chipset press release…

The Apollo MVP3 is a high performance, cost effective, and energy efficient chip set for the implementation of AGP, PCI, and ISA in desktop and notebook personal computer systems from 66 MHz to 100 MHz based on 64 bit Socket-7 super-scalar processors.

The Apollo MVP3 chipset consists of the VT82C598AT system controller (476 pin BGA) and the VT82C586B PCI to ISA bridge (208 pin PQFP). The VT82C598AT system controller provides superior performance between the CPU, optional synchronous cache, DRAM, AGP bus, and the PCI bus with pipelined, burst, and concurrent operation. The DRAM controller supports standard Fast page Mode (FPM), EDO, SDRAM, and DDR SDRAM. The VT82C598AT complies with the Accelerated Graphics Port Specification 1.0 and features support for 66/75/83/100 MHz CPU bus frequencies and the 66 MHz AGP bus frequency. Coupled with BDDR SDRAM II, the VT82C598AT allows implementation of the most flexible, reliable, and high-performance DRAM interface.

Supports 66 / 75 / 83 / 100 MHz CPU external bus speed
PC97 compatible using VT82C586B South Bridge with ACPI Power Management
Includes UltraDMA-33 EIDE, USB, and Keyboard/PS2-Mouse Interfaces plus RTC/CMOS on chip
Single chip implementation for 64 bit Socket-7 CPU, 64 bit system memory, 32 bit PCI and 32 bit AGP interfaces
3.3V and sub-3.3V interface to CPU
3.3V (5V tolerant) DRAM, AGP,and PCI interface
AGP v1.0 compliant
PCI buses are synchronous/pseudo-synchronous to host CPU bus
33 MHz operation on the primary PCI bus
66 MHz PCI operation on the AGP bus
Concurrent CPU and AGP access
Consists of the VT82C598AT system controller (476 pin BGA) and the VT82C586B PCI to ISA bridge (208 pin PQFP)
Built-in NAND-tree pin scan test capability
0.35um, high speed and low power CMOS process

ALI Aladdin V chipset press release

For the sake of keeping it somewhere, here is the ALI Aladdin V chipset press release…

Aladdin V / M1541/ M1543

Aladdin-V is the fifth generation 586 chipset from AcerLabs. It maintains the best system architecture (2-chip solution) to achieve the best system performance with the lowest system cost (TTL-free). Aladdin-V consists of two BGA chips to give the 586-class system a complete solution with most up-to-date features and architecture for the most engaging multimedia/ multithreading OS and software applications. It utilizes the modern BGA package to improve the AC characterization, resolves system bottleneck and make the system manufacturing easier.

M1541 includes the higher CPU bus frequency (up to 100 MHz) interface for all socket 7 compatible processors, PBSRAM and Memory Cache L2 controller, internal MESI tag bits (16K*2) and Tag RAM (16K*10) to reduce cost and enhance performance, high performance FPM/EDO/SDRAM DRAM controller, PCI 2.1 compliant bus interface, smart deep buffer design for CPU-to-DRAM, CPU-to-PCI, and PCI-to-DRAM to achieve the best system performance, and also the highly efficient PCI fair arbiter. M1541 also provides the most flexible 64 bit memory bus interface for the best DRAM upgradeability and ECC/Parity design to enhance the system reliability.

With the AGP interface design, the dedicated PCI_66 AGP interface can be concurrent with CPU and PCI interface. The deep buffer of the read and write buffer design makes the utilization of memory bandwidth more efficient. The interface supports AGP specification V1.0. Supports up to 128 entries table look aside buffer for Graphic Address Remapping Table (GART). The interface not only supports the AGP 66 MHz PCI protocol, but also the AGP 1X and 2X sideband address function.

With the concurrent bus design, PCI-to-PCI access can run concurrently with CPU-to-L2 and CPU-to-DRAM access, PCI-to-DRAM access can run concurrently with CPU-to-L2 access. M1541 also supports the snoop ahead feature to achieve the PCI master full bandwidth access (133 MBytes). M1541 also provides the enhanced power management features including ACPI support, suspend DRAM refresh, and internal chip power control to support Microsoft On Now technology OS.

M1543 provides the best desktop system solution. M1543 integrates ACPI support, green function, 2-channel dedicated Ultra-33 IDE Master controller, 2-port USB controller, SMBus controller, PS/2 Keyboard/Mouse controller and the Super I/O (Floppy Disk Controller, 2 serial port/1 parallel port) support.

The built-in I/O in M1543 is an advanced Super I/O controller solution to the basic IBM PC, XT, AT and notebook peripherals. It incorporates two full function universal asynchronous receiver/ transmitters (UARTs), a flexible high performance internal data separator with send/receive 16 Byte FIFOs. It is suitable for notebook computers since it has Serial Infra Red for wireless communications with other devices. It can swap your drives A & B. It features basic functions such as standard mode, enhanced mode, high speed mode. It supports SPP, PS/2, EPP and ECP parallel port. It also has a programmable baud rate generator. It has high performance power management for FDC, UART and parallel port.

Furthermore, Aladdin V is designed to meet the requirements of all socket 7 process-ors including business, multimedia and high performance CPU file servers.