However before replacing it I wanted to do some tests of standing and peak power consumption of the PC with both the Sweex and Akasa power supplies. I plugged the PC into an energy monitor plug which displays the power consumption instantaneously. In the picture you can see the display showing the PC consuming 118 watts of power.
With each power supply I booted the PC, logged into XP and let the PC settle to a steady state, after all the AV and start up scripts had finished. I then ran sample loads of a full AV scan (heavy disk and CPU use) and then later the GPU benchmark 3dmark03 (heavy GPU use) and watched the peak consumption.
With the Sweex the steady state was around 94 watts rising to a peak of 147 during the AV disk cycle. 3dmark03 peaked at around 144 watts.
With the Akasa the steady state is around 78 watts rising to 127 under similar load. Not very scientific, but I wanted to see if the claims of the Akasa were justified. It certainly appears to use less electricity.
the energy cost savings, while worthwhile, would take a long time to repay, but my plan is that if the dell fails, and one day it will, the PSU can be used in other projects.
Fitting the PSU
Fitting a new PSU in the Dell Dimension is pretty straightforward job.
First you need to disconnect the existing supply from the mains, then remove the side panel.
Remove all the existing power connectors, including the MOLEX white connectors to each disk a, floppy (I don't have one) and CD/DVD drives. The standard MOLEX connectors are white nylon and always seem to hurt my fingers removing them. Then disconnect the existing power supply from the motherboard. There are 2 connectors, a large block and a 4 pin connector for the CPU.
Once all cables are disconnected you can remove the 5 standard PC screws which hold the PSU to the bak plate of the PC. Once free, it's a bit of a fiddle to get the old PSU out and I had to temporarily remove the top CD/DVD combo drive to allow some room.
Once removed it's really doing the whole thing in reverse.
one issue with newer power supplies is the number and range of cables they support. the akasa is not a modular supply, which would mean I could disconnect unnecessary cables at the power supply end. Modern supplies have SATA and PCI-express cables, neither of which are used by the Dell.
As you can see the Akasa cables are neatly sheathed in black nylon, and after a bit of 'dressing' I was able to tie up the unused cables and allow as much air flow space as possible. removing the floppy drive and bracket provides a bit more space. Another nice feature of the Akasa, is the molex connectors for the IDE drives are much nicer and easier to plug in. No pain with these.
Once fired up it all worked first time, which was a relief, as my son was away on a camping holiday, and I didn't want him to return to a broken PC.
Cooling
I did notice that the primary disk drive (located lower front) was reporting slighly increased temperature via speedfan, during heavy load (AV). It was peaking at around 36 degrees which is higher than average and higher than I would like. This may be due to the Akasa fan running slower and hence drawing less hot air from the case, or due to the extra cabling restricting air flow. I'm experimenting with blocking the vaccant floppy case hole with Duck tape, also the hole vents by the PCI cards. Some caution is needed here, but my thinking is that I want cold air to be drawn in from the lower front of the dell, through the front vent holes, over the primary drive (cooling it) and then evacuated vis the PCI blower, case fan or PSU fan. The hole left by the removal of the floppy and the vents by the PCI cards go someway to compromising the venturi effect . I'll keep an eye on this and see if it makes an appreciable difference
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