I have a tray-load iMac revD and have upgraded the Ram and HD

Now I am wanting to overclock the cpu/logicboard [edit]

But before I proceed - is it simply a matter of switching/add/remove jumper clips or is a soldering iron (plus other device) necessary?

tia

attachment?

Try this site for older mac overclocks. Beware - the instructions are a little vague and I would not recommend a novice attempt this overclock.

Thanks - yes I had seen that site and it is a bit vague - hence I took a screenshot of the relevant page and 'tried' to attach it using the file attachment button (appears to have worked for the 80k jpg the 3rd time )

Anyway if someone could tell me if just switching jumpers is necessary I might proceed to extract the cpu card

Nup, there is no jumpers at all that I know of on any iMacs. According to the attachment, you have to desolder and solder in surface mount resistors, something I would not reconmend unless you are quite skilled with a soldering iron.

If you are going to attempt it then make sure you do the following atleast:

use super fine soldering iron tip, the smallest you can find. A SMD (Surface Mount Device) soldering iron would be the most suitable for the job.

Make sure you know which way (orientation) the board is compared to the pics. I know this sounds stupid but its a common mistake.

Along with the fine tip, make sure you have fine solder. Don't use too much, less is more in most instances.

If you have a multimeter (which you should before attempting this), check that each connection parallel to one another are not touching.

Buy some desoldering braid as this will clean up what you heat up with the iron, to remove all old solder before putting on the new stuff.

If you are technical, you can do what I would do. solder some pins above the resistors wide enough to accept a jumper. That way you can easily take them off or put them back on as you please.

Steve

Thanks Guys

Food for thought

De-soldering small components is easy. In most Macs the values of resistors in these banks does not matter and you can use a conductive (circuit trace) pen to bridge the appropriate connections where you would normally be required to solder the resistors back on, this makes life much easier.