This list of frequently asked questions (FAQ) attempts to collect together the experiences of various eMachine owners who have upgraded the CPUs of their computers. eMachines (and its parent corporation, TriGem) provides almost no documentation about what CPUs the various motherboards inside eMachines computers support, so it has come down to brave souls to make (un)educated guesses, and plug new CPUs in with crossed fingers! By summarizing their successes and failures, I hope that this list will aid other budding overclockers in upgrading their computers without causing smoke to rise out!
This FAQ assumes some knowledge of computer terminology and maintainence. If you have to ask how to remove a CPU from a motherboard, or have no idea what a DIP switch is, you probably shouldn't be messing with the inside of your machine.
I host this FAQ at http://www.tmwong.org/emachine-overclockers/.
eMachines does not distribute a motherboard manual with its machines, so finding information on its internals has proved to be a challenging task. I would like to thank the following people for their assistance with gathering information on the Delhi-III.
I maintain this list strictly as a collection of shared experiences. This list is provided as is without any express or implied warranties. While every effort has been taken to ensure the accuracy of the information contained in this article, I accept no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein.
I have not tried every computer/CPU combination reported here, and make no promises that one of them won't inadvertently damage your hardware. If you try any of these, you do so at your own risk, and I accept no resonsibility for the pile of smoking, fused resin that was once an eMachine.
Changing the CPU on your computer will almost certainly void any warranty provided to you by eMachines as well as any those you may have purchased from your retailer. None of these modifications should be attempted by amateurs, or anyone who is averse to the idea of burning up hundreds of dollars of hardware.
eMachines provides no official support in any way for this FAQ.
All of these machines share a common motherboard, the Delhi-III. To quote the official eMachines site, the Delhi-III motherboard is a Micro ATX (ATX V1.2 form factor) motherboard from TriGem Korea, and includes: Socket 7 (321pin ZIF Socket), VIA Apollo MVP3 VT82C598MVP Chip Set VIA VT82C596 PCI bus mastering controller and power management interface ATI Rage-3D Iic built-in AGP graphics accelerator with 4MB SDRAM Crystal CS4235 built-in Sound Blaster Pro, MPC-3, MPU-401 compatible Audio Enhanced Stereo full duplex operation Winbond W83877TF on-board Super I/O. Phew.
CPUs that people have installed with success on a Delhi-III include:
As far as I can tell, the difference between the K6 and K6...+ chips are that the latter are designed for mobile computing applications.
The K6-2 is a drop-in replacement, aside from a few jumper and DIP switch changes. The K6-2+ and K6-III+ require more effort - read Question 4.6.
When putting in the CPU, you will need to adjust three settings: the bus speed, the CPU clock multiplier, and the CPU voltage. The bus speed.... The CPU clock multiplier is how fast the CPU clock runs relative to the bus speed. The CPU voltage is, well, the voltage required to power the CPU.
All of these settings are adjustable by changing either jumper or DIP switch settings. The front side bus speed is set through jumpers J2, J3, J4, J5, and J9; the CPU clock multiplier is set through jumpers J11, J12, and J13; the CPU voltage is set through DIP switch (?). eMachines helpfully included a map (at least inside my eTower 333cs) showing the locations of these jumpers and switches on the motherboard.
The following tables show the settings. Some of them are not documented on the label that attached to the inside of the computer:
Table: 4.2.1. Front Side Bus Speed Speed (MHZ) 60 66 75 83 95 100 Jumper J2 2-3 2-3 1-2 1-2 1-2 1-2 J9 2-3 2-3 1-2 1-2 2-3 2-3 J3 2-3 1-2 2-3 1-2 2-3 1-2 J4 2-3 2-3 2-3 2-3 1-2 1-2 J5 2-3 2-3 1-2 1-2 1-2 1-2 Table: 4.2.2. Multiplier settings Mult 2 2.5 3 3.5 4 4.5 5 5.5 Jumper J11 2-3 2-3 1-2 1-2 2-3 2-3 1-2 1-2 J12 1-2 2-3 2-3 1-2 1-2 2-3 2-3 1-2 J13 1-2 1-2 1-2 1-2 2-3 2-3 2-3 2-3 Table: 4.2.3. CPU voltage DIP switch settings V 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 SW1 Off On Off On Off On Off On SW2 Off Off On On Off Off On On SW3 Off Off Off Off On On On On SW4 Off Off Off Off Off Off Off Off V 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 SW1 Off On Off On Off On Off On SW2 Off Off On On Off Off On On SW3 Off Off Off Off On On On On SW4 On On On On On On On On
Some people have reported that the 2x multiplier setting is actually a 6x for the AMD K6 family.
With sufficient cooling, you can overclock almost anything... Users have reported overclocking the AMD K6-III 450 MHz to 550 MHz (the maximum possible on the motherboard) by using the appropriate settings for the jumpers as set out in Question 4.2. I run my own AMD K6-2 500 MHz at the rated speed, mostly because I don't imagine that 50 MHz will really make much of a difference for my applications.
Just set the jumpers and DIP switches as shown in Question 4.2. K6-III users shouldn't need to do anything special to get TriLevel cache support working.
The K6-2+ and K6-III+ requires more effort than the K6-2 to install. They come with an on-die level 2 cache, which gives anywhere between a 10%-20% improvement in "performance" (for most definitions of "performance" one cares about). The installed BIOS on the Delhi-III can't take advantage of the L2 by itself, so you must run a program at boot time to use the L2.
To install a K6-2+ or K6-III+ on a Windows 9x system, you need to add a program that gets run every time you boot up. Follow these steps BEFORE you install the CPU.
Get the cacheonw.exe executable (unfortunately, I
don't have a copy of it myself).
Put the executable in a convenient location, such as the
\windows subdirectory.
Use the sysedit or notepad programs to
edit the autoexec.bat file.
Add the line C:\windows\cacheonw (substitute
\windows as appropriate).
Next, you need to install the CPU. Don't forget to set the jumpers and DIP switches as shown in Question 4.2!
Finally, you need to disable the off-die L2 cache. When you first boot your machine after installing the CPU, enter BIOS setup and disable the off-die L2. The change you made to autoexec.bat will then activate the on-die L2, and convert the off-die L2 into a level 3 cache.
cacheonw.exe is a real-mode program, and thus cannot run
under Windows ME.
I suspect that the "System" control panel determines the CPU speed based on information it gets from the BIOS. Since the eMachine BIOS pre-dates the K6 500 MHz machines, the BIOS reports the wrong information.
You can put PC100 DIMMs into the memory slots, up to a specified maximum of 128 MB per slot. The BIOS will automatically detect the installed memory size.
You might need to boost the memory bus speed, since Delhi-III-based eMachines come pre-configured with a memory speed of 2/3 the front-side bus speed. To change the memory bus speed, set jumpers J16 and J17 according to Table 5.1.1. Do not change the memory bus speed from 66 MHz if you still have the factory-installed PC66 32 MB RAM installed.
Table: 5.1.1. Memory bus speed jumper settings: J16 J17 Memory Bus Speed 2-3 1-2 2/3 FSB speed (i.e. max. memory speed is 66 MHz) 1-2 2-3 FSB speed (i.e. max. memory speed is 100 MHz)
A gotcha: eMachines didn't label the jumpers. Assuming that you are looking down at the motherboard with the PCI slots vertical and at the left edge, pins 1-2 for J16 and J17 will be the left two pins, while pins 2-3 will be the right two.
You could put PC133 DIMMs into the memory slots, but since the FSB speed doesn't go beyond 100 MHz, you would be wasting your time unless you plan to re-use the DIMMs eventually in a faster machine.
If you feel like living dangerously (I do!), you can install PC100 256 MB DIMMs, which gives the board a max. capacity of 512 MB RAM. eMachines doesn't claim to support 256 MB DIMMs, but I have installed two of them with no problems.
You can put any PCI video card into your Delhi-III. As with many other cheap motherboards, the Delhi-III comes with the AGP-based video "card" built-in, so you have no way to install another AGP-based card. Bummer. Actually, huge bummer, since by and large the only PCI designs available these days are crippled cousins of AGP designs, with the possible exception of (now defunct) 3dfx's Voodoo series of cards.