Has anyone got an opinion on the advantages or disadvantages of leaving a PC running 24/7? I have my main PC switched on all the time - just switching off the monitor when I'm not using it. The system is not overclocked & so just has a standard heatsink/fan & the PSU fan - I figure total 6-8 watts for both (ignoring PSU efficiency as it just complicates things). The MB power usage must be minimal so I tend to ignore. I've set all settings to never switch off - HD is rated at 0.3A, so about 4watts. It's been running more or less 24/7 (apart from holidays) for about 18 months now with no apparent problems. Am I being over-optimistic in thinking that I'm doing less harm to components by leaving it switched on, or should I think about turning it off occasionally. The reason I've started thinking this is that most HDs seem to have a stated working life of 10,000 hours, which I always thought was a long time, but in fact it's only just over a year. Thoughts anyone?

johnr, I find it's like arguing over which way you should load the toilet paper, everyone has an opinion and it really doesn't matter either way. Speaking directly to the hardware, by the time it dies from overuse it's probably out of date anyway so it's not an issue. The hardest part of the hardware is the power surge when you first turn it on so leaving it on or rebooting even each other out. However since you're running windows, you have to consider that the longer windows runs the slower it runs so i find it best to reboot daily however if i miss a day, or or three i don't worry about it. If you have a permanent high-speed connection you may want to consider that you're a target for hackers 24/7 if you leave yourself connected. I suggest to my clients to shut them off when they leave the office and spark them back up in the morning, unless they want to run defrag or anti-virus on their way out of the office and then i suggest they reboot whne they get back in the morning. Just my two cents worth, there is no definitive answer. ciao, wired

You left out static power consumption (as opposed to signalling power consumption) of solid state components. Your cards, memory, mobo, cpu and hard drive logic require power just to stay on. The main power hog of an idle system is the cpu as it requires both static power and signalling power since when windows idles its like a sprinter sprinting in place - the power usage of a cpu idling in windows is pretty close to a cpu running at full load in windows, so figure 50W-60W there. But if you use a software cooler or your bios allows enabling "halt cpu on idle", that 50W goes to about 5W. A 7200rpm hard drive has logic power (5v) as well as motor power (12v), which are each around 3.5W during idle so it appears you considered one and not the other. But to answer your question, keeping the hard drive cool is your main concern. Solid state components show no evidence of longevity-related death but mechanical things of course do, which means your hard drive and fans. Among fans, its usually the 40mm video card or motherboard fan that dies first. When a fan dies it usually results in the system freezing up but not being damaged, so I would not worry about fans since you can replace them as needed. Unless its your psu fan in which case the whole system may fry. Which means your hard drive is the thing to worry about. I keep an 80mm fan pointed right at mine, which is a 24/7 machine. A hard drive's enclosure functions as a passive sink so add some airflow to it and you'll see a 8c-10c temp drop, which will lengthen its life. If I had to guess, I'd say that if every computer was used for decades, the first component (other than fans) to die on 90% of the machines would be the hard drive.

Since opinions are free allow me to offer mine. If you have a apci enabled system your monitor/hd drives/system will power down. In effect this is like powering a 40watt light bulb. My kids consume more power then that by a long shot. It is a known fact that going hot then cold [on and off] can cause more damage and shorten the life of electronic devices. This is due to the expansion and contraction of the components. A surge is a surge whether the machine is on or off. This is why in a thunder/lighting storm you physically disconnect your systems from the wall. Surge suppressors are good but in no way can handle a serious power hit. Your mechanical devices will fail sometime in their mtbf [mean time before failure] ratings no matter what you do. MTBF is a combo of tests not just leaving the drive on until it fails. You can reduce data loss by mirroring and backing up. But that is just common sense. Which brings me to my last point: common sense. Use your computer as it suits you. Forget the rest. It's a tool. I use a hammer for a number of things, some of which it wasn't designed for. It still works. When it's broken I get a new one. Same is true with computers.

I leave mine on all the time. I also have cable internet which some would dispute whether it is good to do that because of hackers. What I do is turn the power "off" on my cable modem. If I can't connect to the internet when it's off then how can anyone get in. Another thing is the power switch. A couple of cases that I had seemed to have a loose switch when I got them. The one that I have now the switch is made nice. No play what so ever in it and I would like to keep it that way. I also heard that going from hot to cold is not good on your hardware too. That is another reason why I would rather just leave it on.

Another thing to keep in mind when running pc 24/7 - DUST. Dust accumulates more quicker! Just make sure you clean it out every once in a while

I have my linux and windows boxes on 24/7. Mainly that my dad uses my windows PC for chatting and games, plus he sometimes has to access my email account. I leave my linux PC on 24/7 as it is a webserver, and also is a FTP server. My sister sometimes leaves her windows machine on also. I have no worries about leaving my systems on 24/7 since I share my internet line (6 megs download/512 kb upload) using a router which has a built-in firewall. Just to be safe I have Norton 2004 Anti-virus with real-time checking enabled on my windows machine since all the viruses out there are aimed at windows.:-) Ben, Pentium 4 1.7GHz, 512 LB Cache 512 DDR RAM PC2700 ATI Radeon 9200SE 128 DDR RAM Western Digital 80GB 7200 RPM