Choosing the Right Power Supply Part I – Calculate the amount of power you need
Scenario :
You just got that droolmaal rig you have been saving for, now you need to figure out which SMPS/PSU you need to power this thing.
Don't, I repeat don't think that getting a cheap PSU is a good idea, people spend over 10k just for the Motherboard and CPU all to get a 450 bucks SMPS in the end.
Consider this, if CPU is the mind of the system, the SMPS is the heart of the system, it provides the power needed to keep the CPU going on. Now why would anyone want a high and brain and skimp out on the heart.
As phoenix said here
http://www.techenclave.com/forums/things-know-before-buying-perfect-graphic-92235.html
When asking for recommendations for a new Rig/PSU I recommend that one goes through this article and mention the power requirements in the new thread.
This guide will help you calculate the maximum power your SMPS needs to have to provide stable operation to the system.
Consider the following components :
Lets discuss all these components in detail :
[BREAK=Power of each component in detail]
1. CPU :
CPU's these days have a TDP (Thermal Dissipation of Power) at about 65W for the mid end and go up to 150W for some high end processors (Current Quad cores). These ratings, keep in mind are absolutely high end readings and the processor may or may not consume this much power at load.
If however you do Over Clock the system, the maximum TDP increases, heres how to calculate the TDP of a OC'd system.
Overclocked TDP = Current TDP * %age of overclock + Current TDP * %age increase in Vcore
Example : Consider a E4300 rated at 65W running at 1.8GHz stock with default Vcore at 1.25V
When OC'd to say 3Ghz at Vcore 1.4V thats
%age of Overclock = (Current OC Speed / Default Stock Speed)
%age increase in Vcore = 1 – (Current Vcore / Default Vcore)
That means :
%age Overclock = 1.66
%age Vcore = 0.12
Which means :
Overclocked TDP for this example becomes = 65*1.66 + 65*0.12 = 115.7W
You can similarly calculate the Power requirements for any other processor by knowing these simple variables (hint : Google for the TDP of your processor)
2. GPU
This is a tricky part as power required by the GPU's increased with every new generation of graphics cards, basically I'll list the TDP of some of the common GPU's bought today and the Overclocked TDP can be calculated in a similar manner as above. For TDP of other GPU's use Google. Always remember Google is your friend.
Disclaimer : These rating are approximate
nVidia :
7900GS : 110W
8500GT : 40W
8600GT : 75W
8600GTS : 110W
8800GTS : 150W
8800GTX : 180W
AMD/ATI :
HD 2900XT : 200W
If using more then 1 card using SLI/Crossfire Technology, add the TDP of both the cards.
If some one knows TDP of more GPU's mention in the comments section and I'll update the article accordingly
3.Motherboard
This is a tricky part, couldn't find information on the TDP regarding the motherboards and then I read this :
Intel 8-core Xeon X5365 V8 Performance Preview
4. HDD's
For each HDD you have connected to the system add 15W at load.
5. DVD RW's
For each DVD RW you have connected to the system add 20W at load.
6. Fans
For each high speed high performance 120mm fan add 10W
For each high speed high performance 80/92mm fan add 5W
For other fans connected the system add 2W
High Speed High Performance fans also include fans installed with the SMPS, CPU and GPU.
7. Other LED's etc
For these add some 15W in general.
[BREAK=Final Words]
Final Words :
Calculated the total power supply you require, now increase the same by 20% for PSU degaradation over time and 15% for future upgrades (or calculate the future power upgrades manually).
The final wattage is what the PSU you get should have at the bare minimum for a stable, smooth and tension free operation of your system.
Other part of the series coming in a few days.
Comments Welcome.
hyeah:
[BREAK=New Addition : A Few Examples]
Consider a very very High end rig
Core 2 Duo E6600 @ 3.6Ghz 1.4V Vcore = 105.3
XFX 680LT = 60W
8800GTX*2 in SLI = 360W
4GB RAM
500*2 GB HDD = 30W
LG H42N DVDRW = 20W
2 120mm fans as exhaust = 20W
1 120mm fan on the CPU with TR 120 Ultra = 10W
Total Power Consumption = 605W
Add some fudge factor (35%) for PSU degradation and upgrading possibilites (20+15) = 211W
Total PSU Wattage you should be looking for 816W continuous at 50degrees
Consider a mid end rig :
Core 2 Duo E4300 @ 3.4Ghz 1.4V Vcore = 130W
XFX 650i Ultra = 60W
8800GTS = 150W
2GB RAM
500*1 GB HDD = 15W
LG H42N DVDRW = 20W
1 120mm fan as exhaust = 10W
Stock cooling fan on GPU = 10W
Stock cooling fan on PSU = 5W
Total Power Consumption = 400W
Add some fudge factor (35%) for PSU degradation and upgrading possibilites (20+15) = 140W
Total PSU Wattage you should be looking for 540W continuous at 50degrees
Consider a low end rig :
Core 2 Duo E4300 @ 1.8Ghz 1.4V Vcore = 65W
XFX 650i Ultra = 60W
8500GT = 35W
2GB RAM
250*1 GB HDD = 15W
LG H42N DVDRW = 20W
1 80 mm fan as exhaust = 5W
Stock cooling fan on GPU = 5W
Stock cooling fan on PSU = 5W
Total Power Consumption = 210W
Add some fudge factor (35%) for PSU degradation and upgrading possibilites (20+15) = 74W
Total PSU Wattage you should be looking for 284W continuous at 50degrees
Scenario :
You just got that droolmaal rig you have been saving for, now you need to figure out which SMPS/PSU you need to power this thing.
Don't, I repeat don't think that getting a cheap PSU is a good idea, people spend over 10k just for the Motherboard and CPU all to get a 450 bucks SMPS in the end.
Consider this, if CPU is the mind of the system, the SMPS is the heart of the system, it provides the power needed to keep the CPU going on. Now why would anyone want a high and brain and skimp out on the heart.
As phoenix said here
http://www.techenclave.com/forums/things-know-before-buying-perfect-graphic-92235.html
Also, some people have this notion that when you buy a SMPS of high power rating say 600W it will consume 600W all the time. This in NOT TRUE, a SMPS consumes only that much power which is required at that particular moment by the system.
When asking for recommendations for a new Rig/PSU I recommend that one goes through this article and mention the power requirements in the new thread.
This guide will help you calculate the maximum power your SMPS needs to have to provide stable operation to the system.
Consider the following components :
- CPU
- GPU
- Motherboard
- HDD's
- DVD RW's
- Fans
- Other LED's etc
Lets discuss all these components in detail :
[BREAK=Power of each component in detail]
1. CPU :
CPU's these days have a TDP (Thermal Dissipation of Power) at about 65W for the mid end and go up to 150W for some high end processors (Current Quad cores). These ratings, keep in mind are absolutely high end readings and the processor may or may not consume this much power at load.
If however you do Over Clock the system, the maximum TDP increases, heres how to calculate the TDP of a OC'd system.
Overclocked TDP = Current TDP * %age of overclock + Current TDP * %age increase in Vcore
Example : Consider a E4300 rated at 65W running at 1.8GHz stock with default Vcore at 1.25V
When OC'd to say 3Ghz at Vcore 1.4V thats
%age of Overclock = (Current OC Speed / Default Stock Speed)
%age increase in Vcore = 1 – (Current Vcore / Default Vcore)
That means :
%age Overclock = 1.66
%age Vcore = 0.12
Which means :
Overclocked TDP for this example becomes = 65*1.66 + 65*0.12 = 115.7W
You can similarly calculate the Power requirements for any other processor by knowing these simple variables (hint : Google for the TDP of your processor)
2. GPU
This is a tricky part as power required by the GPU's increased with every new generation of graphics cards, basically I'll list the TDP of some of the common GPU's bought today and the Overclocked TDP can be calculated in a similar manner as above. For TDP of other GPU's use Google. Always remember Google is your friend.
Disclaimer : These rating are approximate
nVidia :
7900GS : 110W
8500GT : 40W
8600GT : 75W
8600GTS : 110W
8800GTS : 150W
8800GTX : 180W
AMD/ATI :
HD 2900XT : 200W
If using more then 1 card using SLI/Crossfire Technology, add the TDP of both the cards.
If some one knows TDP of more GPU's mention in the comments section and I'll update the article accordingly
3.Motherboard
This is a tricky part, couldn't find information on the TDP regarding the motherboards and then I read this :
Intel 8-core Xeon X5365 V8 Performance Preview
Since I am covering case fans later onwards, for a motherboard add 60W of Power.
4. HDD's
For each HDD you have connected to the system add 15W at load.
5. DVD RW's
For each DVD RW you have connected to the system add 20W at load.
6. Fans
For each high speed high performance 120mm fan add 10W
For each high speed high performance 80/92mm fan add 5W
For other fans connected the system add 2W
High Speed High Performance fans also include fans installed with the SMPS, CPU and GPU.
7. Other LED's etc
For these add some 15W in general.
[BREAK=Final Words]
Final Words :
Calculated the total power supply you require, now increase the same by 20% for PSU degaradation over time and 15% for future upgrades (or calculate the future power upgrades manually).
The final wattage is what the PSU you get should have at the bare minimum for a stable, smooth and tension free operation of your system.
Other part of the series coming in a few days.
Comments Welcome.
hyeah:[BREAK=New Addition : A Few Examples]
Consider a very very High end rig
Core 2 Duo E6600 @ 3.6Ghz 1.4V Vcore = 105.3
XFX 680LT = 60W
8800GTX*2 in SLI = 360W
4GB RAM
500*2 GB HDD = 30W
LG H42N DVDRW = 20W
2 120mm fans as exhaust = 20W
1 120mm fan on the CPU with TR 120 Ultra = 10W
Total Power Consumption = 605W
Add some fudge factor (35%) for PSU degradation and upgrading possibilites (20+15) = 211W
Total PSU Wattage you should be looking for 816W continuous at 50degrees
Consider a mid end rig :
Core 2 Duo E4300 @ 3.4Ghz 1.4V Vcore = 130W
XFX 650i Ultra = 60W
8800GTS = 150W
2GB RAM
500*1 GB HDD = 15W
LG H42N DVDRW = 20W
1 120mm fan as exhaust = 10W
Stock cooling fan on GPU = 10W
Stock cooling fan on PSU = 5W
Total Power Consumption = 400W
Add some fudge factor (35%) for PSU degradation and upgrading possibilites (20+15) = 140W
Total PSU Wattage you should be looking for 540W continuous at 50degrees
Consider a low end rig :
Core 2 Duo E4300 @ 1.8Ghz 1.4V Vcore = 65W
XFX 650i Ultra = 60W
8500GT = 35W
2GB RAM
250*1 GB HDD = 15W
LG H42N DVDRW = 20W
1 80 mm fan as exhaust = 5W
Stock cooling fan on GPU = 5W
Stock cooling fan on PSU = 5W
Total Power Consumption = 210W
Add some fudge factor (35%) for PSU degradation and upgrading possibilites (20+15) = 74W
Total PSU Wattage you should be looking for 284W continuous at 50degrees
