Power requirements for 4850 vs 4890

I am thinking of doing 1 of 2 things.

Plan 1:
Get components myself and build my computer.

Plan 2:
Get a prebuilt computer and switch out the video card.

Now my question comes from my plan 2. Most of the prebuilt computers with an I7 that are sub 1K have a "low end" graphics card(I include quotes because even the low end cards still beat out my current one). I currently have a 4890 in my hands and am thinking of, as I said, switching the graphics cards and basically having the computer I would have build. However the issue comes with the power supply. If i build my own then I know exactly how much power I am getting and what it can handle, however not in this case. Most computer dont state how powerful their PSU actually is which is a tad irking. Now what is the power requirement difference between a stock speed 4890 and I am assuming a stock speed 4850? Would I be alright just switching it out? Or would I go past the supplied power? I was told that I would need to replace the power supply if I wanted to put additions in, but the sales clerk either A) was trying to sell me a power supply, or B) though I was going crossfire or adding stuff not switching components.

thanks in advance
10 answers Last reply
More about power requirements 4850 4890
  1. Just build it yourself. It will be cheaper and then you can be sure all of the components are of a quality brand and exactly what you want.
  2. A HD4890 draws far more power than a HD4850: It needs 2 6 pin PCI-E connectors while the HD4850 requires only one, I would not risk it, not on a new system.
    It would be a fair bit cheaper to build yourself but it is not something to rush into, it's a steep learning curve at the beginning and rushing into things WILL cause mistakes. (OK, so you could be an IBM Supercomputer designer, I do n't know!).
  3. I wouldn't say there's a steep learning curve at all. Actually putting together a computer is really quite simple. It's picking out the part's that requires some knowledge and that's what sites like this are for. Run the list of parts you are considering past the users on here and they will tell you if you are making any errors.
    Really it's kind of hard to mess up. He is building and i7 system. Obviously you get an i7 cpu and an appropriate motherboard(x58). i7 uses DDR3 ram. Any hard drive and dvd drive will do but at this point SATA drives are preferable. An i7 system will have a full ATX motherboard so you need a full ATX case. You want a PCIe video card. The only tricky part is picking out a quality PSU that is right for your system and the OP seems to already understand that.
  4. i would look around cause there are some sweet deals on pre built PC but if you can make that same one cheaper go right a head some company's offer warrants plus you get Windows Crappy Vista with it woo :o
    and some times they load it up with there advertisements and junk like that

    but like i said pick whats right to you if you like to put PCs together you can always rip a pre built one apart and put it back together LOL!
  5. If you are going to use only 1 video card, a cheap 500W power supply should be just fine.
  6. There are PSU calculators that can help you select an appropriate power supply. Any of the major power supply manfucaturers will have one. You just need to have a rough idea what's going in your system, but pay special attention to the video card power connections.
  7. The first time I built my computer, I messed up on half the stuff (forgetting the IO panel, forgetting the CPU heatsink backplate on the motherboard, etc)
    and it only took me about 6-7 hrs. But I saved like $400 by building my own system, so it was well worth it.
  8. thanks for all the replies and the pointer to power req calculators. I found that for the stuff I am getting just switching out will probably not work out well since it appears the companies use the least amount as possible and the 4890 seems to take ~100Watts more which is problematic with the way companies prebuild PCs.

    With that in mind it looks like I will just be buying the parts separately and putting it together.

    Any advice on installing the mobo? That is really my most worry some part of it. I dont have a problem working with the computer and feeding power to fans, putting slots in, but mounting the mobo and socketting the CPU and CPU cooler are way too crucial for me, a first timer, to just go in head first.
  9. you fool! why do the research first and miss out on all the fun of getting it hopelessly wrong! ;)

    Have a look here, you should find this useful:

  10. you just screw the motherboard into the case. That part isn't difficult. The cpu is even simpler. The cpu fan/heatsink used to be quite annoying but these days it's really easy as well.
    The hardest part by far of every computer I've built is connecting the front panel switches/lights/usb to the tiny pins on the motherboard.
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