Choosing Compatible PSU

Power Supply is the fourth important component in Dell E521.

The cost and the power of the power supply really depends on which graphic card you are going to get.

The strong power supply is always the best but it is also necessary to avoid unnecessary power usage and it is always attractive if the power supply is operating at low noise.

The amount of Power usage in E521 is roughly about 530Watt max. Of course, this will rise if you Graphic card eats more than 200Watt at ''Load'' but I would say 520Watt to 650Watt is sufficient. However, if you have sound card and a lot of USBs plus a lot of Fans and additional network card or whatever the device you have in your case, you need to have 600Watt for sure just in case. (My experience was 550Watt but I want the reader here not to encounter the power shortage just in case)

My previous PSU was 450Watt and I had sapphire HD3850 at the time. Rarely, the power stopped without any notice. Obviously, the power was not sufficient.

Also, generally, the peak wattage is usually 50watt higher than the normal wattage so there is no harm buying 520Watt PSU. (the max wattage will be 570Watt in this case)

I don't own it but I personally like this particular PSU 500Watt Stealth Xtreme PSU

Some quality powersupply like the link above is well designed so there is no need to worry about the shortage of power supply( I was modding my teacher's computer and bought it for E8400 and HD4830) . But I still do doubt the power shortage in case I upgrade my graphic card in future so

you can get the 700Watt version of it.

They are pretty expensive but it is worth the price compared to the cheap ones.

In any case, it's not a bad idea to buy a powerful powersupply if you are planning to build your own computer after your E521 dies.

Also, you must get the brand PSU such as OCZ, Corsair, Hiper, thermaltake etc etc.. Because they mostly aim to manufacture their PSU for gamers. The cheap cheap unknown ones are not recommended because they are often not stable when you play games for a long period of time.


There are some webpages that calculates the amount of wattage you need. Usually, they are way too much but this particular one looks convincing to me:

http://www.journeysystems.com/?power_supply_calculator

According to the site, the minimum amount of my PSU should be 430Watt.

In my system, I have HD4850, two hard drive, soundblaster, two optical drive and 2 fans.

If your power supply is not giving enough energy to every components of your system, you will encounter the sluggish performance. It is so obvious that you can even see it clearly with your eyes.



Almost, all ATX PSU can fit into E521 providing you have checked the following requirements before you buy the new one.

1. The dimension of the PSU should be:

Width - 150mm or 5.9 inch
Length - 140mm to 160mm (150mm is standard)
Height - 86mm or 3.4 inch (this must be 86mm)

2. PSU with PCI Express power cable.


3. More than three sata power cable included. Four sata cable is recommended since there are max four Sata device in E521. If you have additional internal Sata (I or II) hard disk and additional Sata DVD rom, then you need four Sata power cable.

Depending on the location where you plug in the AC adapter on your new PSU, as soon as you screw the new PSU, the frame will bend a little. But this is not a big issue.

Four screws are usually included in the new PSU box. if not, you can still use the current screw that is holding 305watt psu.

The locations of the screw holes are virtually the same as the dell PSU but occasionally, depending on the PSU, you will only have to use 3 screws. In that case, make sure you screw them tightly.



The Fan intake area should face down when you install the new PSU.




Currently, I have the above: Hiper HU4M530 530Watt power supply.
Please look at this official site to see the spec.

This fits in nicely and everything is working fine with my HD4850 graphic card and AMD 6400+.


However, the problem with this power supply was that the Sata cable couldn't reach down to the Hard drive due to it's length so I bought additional Sata power splitter.



Additionally, you can open up your new PSU and install your desired Fan to reduce the noise if it is too loud for you.

I have replaced this Hiper fan to Noctua Fan.

The dimension of the PSU Fan is exactly the same as the case front fan.

Width - 120mm
Length - 120mm
Height - 35mm OR 25mm (I personally recommend 25mm ones)

IF you are going to change your PSU fan, the place to look for is the amount of dB, how much sound it dissipates and the CFM, the amount of airflow. Normally 54CFM with 17dB is the standard choice here.



(I will update this part if necessary. ) Please contact me if you have any questions. Thank you.