Okay I'm looking into getting a Antec EarthWatts EA-500D Green 500W PSU and I was browsing the feedback on Newegg. One review says it doesn't work well with low end UPS. I read the FAQ at the top of the forum already and from what I tell UPS is some kinda backup failsafe incase of power surges or something.
If the UPS is a reliable, good UPS, any computer will work fine connected to it.
The function of a UPS is exactly what the name indicates "Uninterrupted Power Supply". If the 110 Volts AC power coming in is clean, reliable, and uninterrupted, then there is no need for a UPS. If not, the UPS unit has storage batteries that will provide a few minutes of power in case there is a power outage.
APC units are good UPS units. It should be sized to 80% of the PSU in your computer + the wattage of the display (50 watts?)
UPS capabilities are measured in VA (volt-amperes). When looking at volt-amperes, find 60% of that value, and that's the maximum actual wattage the UPS can support. So for example, you have a 1500VA UPS, 60% of it is 900, therefore the maximum power output it can support is 900W.
So my advice for you is to get a UPS that is minimum 950VA for just your PC and monitor.
It turns out that most PC power supply units with active power factor correction (PFC) do not work well with lower-cost uninterrupted power supplies (UPS), e.g. battery back-ups. This I learned the hard way, as my Antec EarthWatts EA 500 PSU, which I adore, will go dead the second the battery on my APC Back-UPS BX1300LCD kicks in.
That’s because APC’s Back-UPS units output power, when on battery, as a modified sine wave, rather than a true sine wave.
In short, if you send a high-end PSU the current created by a lower-end UPS, the PSU’s built-in power factor correction hates it, and cuts power to the PC immediately. As in, the exact thing you bought the UPS to prevent in the first place is exactly what happens.
The biggest selling point of the Pro-Source 1500 is in its pure sine wave output. Pure-sine wave output is usually only found in high end UPSes. Why is this important? Many sensitive electronic equipment have problems running on a simulated or modified sine wave output. Because a modified sine wave operates in peaks, such things as audio equipment, displays and products with lower quality power supplies can show anomalies such as lines, humming, and other distortion. In some severe cases, equipment can even be damaged.
950 VA APC's BackUp-UPS - Modified Sine Wave - Problem
950 VA APC's Smart-UPS - Pure Sine Wave - No problem