5v reading critical?

[VideoPhreak]

I am confused here. I went out and bought a new powersupply today to see if it made my system more stable at speed. The main reason I did this was to see if I could get the 5v reading up a little higher than 4.83v under load which is what was happening when I played Unreal Tourney (sometimes it went as low as 4.79v). I put a 400W unit in place of the 300W that my Antec case came with and I only get to 4.88 under load now as opposed to 4.83v not hardly worth the $79.00 I spent on the power supply right? so then if another 100 watts wont stabilize the 5v reading what will? and is this a critical voltage and why is it critical? and if it is critical should I exchange this power supply for a 600W for example?
I now have my Athlon 1333 running at 1512 with the following settings:

CPU set to 100 Mhz (jumper on the mobo)
Multiplier set to 12.5 (jumper on the mobo)
CPU Core set to +.1v (jumper on the mobo)
DDR set to default (+.1v) (jumper on the mobo)
FSB at 116 (BIOS setting)
this yields a readout in the boot sequence of 1508 Mhz and 1512 in MBM 5+ (i guess MBM see's the 12.5 multiplier as a 13.0)
Current temps are 38 Idle/41 Loaded (not bad ?)

Is this the limit? or does it make sense to reduce the multiplier and go for a higher FSB setting in bios to get a higher OC Speed.

[Placid]

The 5v can cause problems when overclocking but not always.
Its not critical that it reads 5.0v.
Most people do not have problems until 4.7v or so.

Yes I would lower the multiplier and raise the fsb.
I personally would rather run at 155x10 than 133x11.5.
You get better memory bandwith that way.
You are not making very good use of your 2100 memory and 266 cpu running it at 100fsb.

[Fink]

Just to let you know that it might be the winbond chip reading the voltage low. My IWillKK266 reads 4.71-4.82 V on the 5 V rail reported both my MBM and in BIOS. In actuality, the PS is supplying 5.02-5.05 V checked by the trusty Fluke multimeter. I too got into a panic over a low 5V reading and purchased a new 400W PS not realizing that it was just the system. Thank goodness for liberal return policies!