cetkat

Compaq Presario S4020WM
2.0 AMD Athlon XP
Northbridge Chipset: KM266 / VT8375
1.0 Gig RAM (maxed)
250W PSU (which will be upgraded)
4x AGP Slot (basic universal)

I need to update my system from integrated video to AGP so I can make full use of my new 22" LCD & obtain better video playback. I'd like for the new card to handle as much as possible in order to downplay the lower system RAM. I don't care much about gaming, but I want HD vids to work flawlessly. So far, I've come across two options:

SAPPHIRE 100258L Radeon HD 3650 512MB 128-bit GDDR2 AGP 4X/8X $90

SAPPHIRE 100228L Radeon HD 3850 512MB 256-bit GDDR3 AGP 4X/8X $120

They have better speeds than most others offered at newegg.. and finding 4x AGP cards with a good memory base elsewhere has been difficult. I'm not looking for an expensive card, so $120 is pushing it - but I could manage if it was worth it.

The 3850 has about 3x the Stream Processing Units and a higher bit rate; but, the 3650 is $30 cheaper. The 3650 also takes less power to run - so I'm thinking that I may be able to get away with a borrowed 350W PSU rather than buying one. My pc runs fine on 250W now.. I wouldn't think a low-powered card would need more than an additional 100W - or am I wrong? Anyway, the card is only meant to run in this low-end system, as I will definitely switch to PCIe when I get to swapping out the Board. So it doesn't have to be great - just great for this computer.

Which card do you think I should put in my system? Are there others that I haven't considered and should?

roadsweeper

You may not be able to run HD vids flawlessly. Even though you have a better card, the CPU will still do a lot of the processing, there is no way to offload all the CPUs work onto the GPU, it will do as much as its been intended to do by the manufactuer. The main thing thats going to really inhibit this is your RAM, but theres not really much you can do about it.

The difference between those two cards is minimal, theres not a lot in it. Peronsonally.. if your determined to get a new card, I'd go for the cheaper one and save up more for a new computer, but in the end, its a new computer you are going to need if you want to upgrade further. If you want to go to PCI-E you will need to replace more or less everything, definately the PSU (750W+), motherboard, RAM, gfx card, CPU.

Its up to your budget. If your budget is tight and takes you a long time to save, I'd go for the cheaper of the two cards. If you can save pretty quickly, and can live with the gfx for a while longer, dont replace it at all and go straight out for a new computer. You can get some pretty nice tower bundles out there if you look (case only, no monitor etc)

Prob not the answer you're looking for, but thats what I would do

cetkat

Thank you. That's actually quite helpful.

I was thinking the cards would probably act about the same on my system, even with their differences - but I wasn't sure. I didn't want to get the cheaper one if the other would be a significant improvement. The more affordable one definitely sounds like the way to go now.

I know that this is the last upgrade I can do for this computer, but considering that I don't have the money for the newest and greatest right now - I think it's worth it. And, actually.. now that I think about it.. I should probably do this update for my Compaq & then just make a third system, rather than gutting this one. That way I don't have to waste the card.

As for the flawless video.. yeah, I thought I was aiming a bit high on that.. but one can hope, right?

What do you think about my PSU? Would a 250W to 350W upgrade handle the switch from onboard to AGP?

koala

If you're switching from integrated to AGP, your PSU will need a minimum of 18A on the +12V line. Check the label on the side of the PSU for this info.

Enter your full system specs into this power calculator and set Capacitor Aging to 25%. Click the Calculate button, then add 40% to the total to allow for PSU inefficiency. Post back with the total plus 40%.

The HD3850, although more expensive, will give better performance due to its 256bit GDDR3 RAM.

cetkat

I'll have to dig the PSU out of storage to check the 12V Amp.. didn't realize that was a factor. I'm thinking that it should be powerful enough though, considering my old weak one puts out 14A.

As for the calculations:

3650
226w -> 372.4w

3850
283w -> 396.2w

So it's pretty close. Am I right to think that I could determine any inefficiency with a multimeter and go from there?

Also, would the 4x slot be able to take advantage of the 256bit GDDR3 RAM or would it get slowed down?

koala

There's nothing you can do about PSU inefficiency. A multimeter would tell you the output on each line and if it's within the +/-5% range, but there are no settings or changes you can make to improve the situation. All PSUs have this problem. Even the best are only 80-85% efficient and this number decreases over time. Older generic units can be as low as 50%.

If you decide on the HD3850 card, a good quality 450W PSU with over 18A/+12V will be ok. More amps would be better though.

If your motherboard doesn't support x8 AGP, a card with 256bit GDDR3 won't be slowed down by using a 4x slot.

cetkat

Right, I'd just have to buy another PSU.. but it would tell me how well it is working for the moment. I may have time to get a higher PSU later, rather than before.

Excellent. Thanks!

cetkat

koala, I'm trying to find some brand PSU's in the 400-500W range, but the specs are all saying 17A. Going higher in watts I can find some 30A's, but that increases the price quite a bit. Do you have any suggestions for a qualified 450W that isn't a generic?

emosun

If you just want HD playback a 3450 would be plenty as most modern gpu's (even low end ones) will play HD flawlessly. The only problem will be your cpu as HD playback requires a lot of cpu power and at least two cores to play smoothly.

koala

I was reading recently on a video forum where it said to play high quality H.264 videos you need at least a 2.8GHz dual core CPU. Other people say they have no problems with a 2.2GHz. Either way, your 2GHz Athlon XP might struggle with HD quality.

Corsair 450W (85% efficiency, 33A/+12V) - $60 after rebate.

emosun

I know my pentium d 2.8 can play HD , but not perfectly. Maybe 85 to 90% perfect. It laggs generally when there's full movement in the video. Even with a clean install and the latest drivers it's just a solid hardware limitation. Which is why I don't think a single athlon xp could do it.

cetkat

Thanks for the Corsair link! I appreciate all the help.

Still up in the air on which card I'll get, but I'm leaning towards the 3850. It definitely can't hurt, and since I'm going to have to get a new PSU.. I may as well make use of it, right?

emosun

Well if your just want HD , that's a basic thing in modern gpu's and just a low end 3450 would do it the same as a 3850. Essentially your buying a ferrari for the cup holders.

But I still think your cpu isn't going to be able to do it.

cetkat

Do you mean the 3650? Sapphire doesn't make a 3450.. Are you thinking of something else that may be a better fit?

I understand you with the HD - it may not make any difference at all. I will have a bottleneck at my CPU regardless. But it seems like I would at least get a slight performance increase with other video that doesn't tax my CPU. (Though, admittedly, the difference may not be noticable)

They're both ferrari's - I'd just be adding the nicer cup holders.

Plus, the 3850 does have free shipping and a $10 rebate.

emosun

Ah , I forgot you had an agp board. In that case I guess the 3650 would be best.

cetkat

Yes.

Thanks for all the help!