corsair 650w/750w crossfire 4890?

CrinkElite

Hi I'm in the process of upgraqding my power supply because i just got a 1gb 4890 and my old xilence 600W is not up to the job (31A on the 12v rail)

UI ordered a corsair 750W (60A on the 12v rial) from pixmania for E123 deliverd, thing is i got an email this mornig saying that the product is out of stock untill the 11th of next month, i realise that that this amperage may seem a little overkill but I would like to have the headroom for future upgrades, If I'm going to buy a psu I don't want to have to do it again for a very long time. i may go the crossfire route seeing as i got the 4890 so cheap.
anyway pixmania do have a corsair 650W (52A on the 12v rail) and it's 25 quid cheeper. do you think this could handle a the crossfire setup? or should i just be patient and wait till the get them in stock?

thanks for reading.

uberpixie

For the 4890 I would go for the 750W if you are def going crossfire down the line.
(4890s are meant to be a lot more thirsty for power than the 4870s)

Komplett show x2 corsair 750W in stock for 109 Euro.
http://www.komplett.ie/k/ki.aspx?sku=340678

CrinkElite

thanks. I think you're right gonna go with pixmania seeing as i already placed the order and komplett dont accept laser. Just have to be patient:mad:

Effluo

don't you have to go for the corsair 750watt because the 650watt only has 2 pci-e power connectors and you need 4 to power two 4890s?

Kiith

A 650W PSU isnt enough for a 4890? Hmm, looks like i will have to get a new one then. Had hoped my 500W woud be enough.

CrinkElite

in theory the xilence 600w should be enough but it's actualy a piece of crap. you're power supply may well have enough power in it to run the card.
you need to take a look at the sticker on the power supply. the important factor is the 12v rail, this should be clearly maked. sometimes there are more than one 12v rail in which case you should just add the values together. my current psu has a total of 31amps spread bewteen 2 12v rails (16A+15A)
this apparently is not enough (or not enough for sustained gamming). the wattage of a psu does not seem to represent it's true output as there are different levels of efficiency. My psu is not efficient so the wasted input power is converted into heat which in turn decreases the efficiency even more.
I would definately have a look at the sticker before ordering a new psu. in some cases a 500W could be enough.
if you have a decent brand you're probably safe.

CrinkElite

Effluo wrote: »

don't you have to go for the corsair 750watt because the 650watt only has 2 pci-e power connectors and you need 4 to power two 4890s?

I recieved two molex to six-pin adaptors in the box with the card

Solitaire

Then its time for some maths: Tote up all the 12V current draw for your PC's components and add the 30A that the dual HD4890s will need at peak load. Even if you're not going to OC then you'll only have ~22A for the rest of your PC so it depends on the power requirements of the rest of your components - CPU, mobo, RAM, HDDs, optical drives, PCI(e) cards, fans and external/USB devices. We might be able to give you a better idea if you told us all that but, off-hand, even without OCing I'd say that any PC that could actually utilize the power of CFd HD4890s would have sufficient 12V current draw to make 52A (i.e. TX650) a bit too close for comfort

CrinkElite

Solitaire wrote: »

Then its time for some maths: Tote up all the 12V current draw for your PC's components and add the 30A that the dual HD4890s will need at peak load. Even if you're not going to OC then you'll only have ~22A for the rest of your PC so it depends on the power requirements of the rest of your components - CPU, mobo, RAM, HDDs, optical drives, PCI(e) cards, fans and external/USB devices. We might be able to give you a better idea if you told us all that but, off-hand, even without OCing I'd say that any PC that could actually utilize the power of CFd HD4890s would have sufficient 12V current draw to make 52A (i.e. TX650) a bit too close for comfort

that sounds about right. thanks for the heads up, I'm gona hold on for the 750W. Do you think that Kiith's 500W (assuming its 80+ efficent) could handle just one 4890?

TerrorFirmer

A good quality 500w would be OK. The thing about cheaper supplies is that let alone their gross inefficency, the advertised output is often overexaggerated, and even at that, that maximum output is only sustainable for a very short period of time. EG, it might say '600W Psu', but it reality it might only be able to output 450w for 2 minutes, or as well as 400w sustainably. I'm not saying that the Xilence is anywhere near that bad mind, but just that you really have to be careful with cheap supplies.

Just looking quickly at reviews of that Xilence its got terribly unstable 12v rails which is always going to be a disaster in a high performance games machine. Its not the 31a thats inherently the problem its the quality of the psu.

Solitaire

^ +1

TerrorFirmer wrote:

it might say '600W Psu', but it reality it might only be able to output 450w for 2 minutes, or as well as 400w sustainably.

... Or it might just be an average PSU, but based on older topology. Pentium 3 and AGP are predominantly 3.3/5V powered systems with 12V used for HDDs and little else, and some cheaper PSUs you may find might be based on obsolete designs from that period, so even if it was say 500W it might only manage 150-200W on the 12V rail(s). P4-based systems only started the move away from that and it was only heavy PCIe adoption that forced high-output 12V PSUs to predominate, so there are still many PSUs out there built to support P3/early P4 AGP systems.

Lots of ppl here can answer Kiith's question but he/she has to tell us the exact make/model they have at the moment before we can give any kind of real answer.

CrinkElite

do you think that a corsair 750W's topology will have a good service life or are there new technologies planned which will make it obsolete?
http://www.corsairmemory.com/products/tx/default.aspx

PogMoThoin

CrinkElite wrote: »

do you think that a corsair 750W's topology will have a good service life or are there new technologies planned which will make it obsolete?
http://www.corsairmemory.com/products/tx/default.aspx

They make an excellent psu, I've a 750W here and its got 4x 8pin pcie for all future upgrades, its also totally inaudible, unlike the last OCZ which even called itself StealthXtreme (which was the reason I changed it). Can't recommend Corsair highly enough.

TerrorFirmer

Solitaire wrote: »

^ +1



... Or it might just be an average PSU, but based on older topology. Pentium 3 and AGP are predominantly 3.3/5V powered systems with 12V used for HDDs and little else, and some cheaper PSUs you may find might be based on obsolete designs from that period, so even if it was say 500W it might only manage 150-200W on the 12V rail(s). P4-based systems only started the move away from that and it was only heavy PCIe adoption that forced high-output 12V PSUs to predominate, so there are still many PSUs out there built to support P3/early P4 AGP systems.

Lots of ppl here can answer Kiith's question but he/she has to tell us the exact make/model they have at the moment before we can give any kind of real answer.

On that note, X-Power PSUs in Maplins. Advertised as 450, 500 and 700w, but each, even the 700w model, only has a maximum of 18a on the 12v, total joke! I noticed that they're finally revised it, so that the 12v is now dual rail and overall about 36a, but I'd say countless people got caught out terribly until now. I wonder are the quality any better though.

CrinkElite

TerrorFirmer wrote: »

On that note, X-Power PSUs in Maplins. Advertised as 450, 500 and 700w, but each, even the 700w model, only has a maximum of 18a on the 12v, total joke! I noticed that they're finally revised it, so that the 12v is now dual rail and overall about 36a, but I'd say countless people got caught out terribly until now. I wonder are the quality any better though.

Maplin is a BAD joke but sadly there the only people in galway aside from pcworld (to the best of my knowlege) that deal in computer components.

PogMoThoin

Par for the course as far as bricks and mortar shops are concerned, avoid them and shop online for value for money

CrinkElite

does anyone know if they stock any half decent cpu coolers, and If so what brand/specs should i look out for. Don't have to be great just a decen't enough one thats not too loud, If you could recomend a decent paste that would be great too.
sorry for going off topic.:o

ps I don't mind paying a bit extra as it'd cost a bit to get posted out anyway

PogMoThoin

I recommend shopping here as they ship by An Post the following day, You'll have it within 3 days. Much better stock and prices than rip-off Maplin. They'll take Laser also and if You live nearby You can collect and pay cash

Most coolers come with thermal compound of some sort, but if You're looking for some better stuff Arctic Silver is the most recommended.

CrinkElite

so copper and allunminium is the way to go? do I need a thermal paste remover or can this be done with household cleansers?

should I start another thread for this?

thanks in advance

PogMoThoin

What cpu have You got? This will determine which cooler

Acetone or unscented nail varnish remover will remove thermal paste

CrinkElite

core 2 duo e6600 @ stock-2.4ghz
2gb DDR2 ram on one stick
Gigabyte GA-965P-S3 mobo
ATI Radeon 4890 1GB. (using an nvidia 7600 for the next week)
Xilence 600W PSU - switching to a corsair 750W soon
WinXP 32bit SP3 - moving to vista soon.

boards won't let me put this in my signature till i get more posts

PogMoThoin wrote: »

What cpu have You got? This will determine which cooler

Acetone or unscented nail varnish remover will remove thermal paste

PogMoThoin

Get this Arctic Freezer Pro, amazing little cooler and perfect for a dual core, nice price too

CrinkElite

PogMoThoin wrote: »

Get this Arctic Freezer Pro, amazing little cooler and perfect for a dual core, nice price too

thanks for the sdvice, I forgot to mention that I am considering an upgrade to a q6600/q6700 in the near future (depending on finances) may try and get it to 3.0ghz or alittle higher, do you think that this fan would suit both?

I appreciate the info by the way.

PogMoThoin

No, although it'd handle a quad fine at stock, it might struggle with an overclocked quad as quads produce more heat than dual cores. For this You'd need a much better cooler the likes of a Thermalright Ultra coupled with a good fan or a Tuniq Tower (comes with a fan)

CrinkElite

PogMoThoin wrote: »

No, although it'd handle a quad fine at stock, it might struggle with an overclocked quad as quads produce more heat than dual cores. For this You'd need a much better cooler the likes of a Thermalright Ultra coupled with a good fan or a Tuniq Tower (comes with a fan)

those look like some crazy things to have to squeez into a case but iguess thats's what it takes,that custompc cooler review site is exactly what I've been searching for.

thanks again

I think I might go for the artic cooler you suggested as it is rated very higly on that site and I'm not 100% sure if I'll get that quad, great price too so not a major setback if i decide i need a little more.

PogMoThoin

Custom PC reviews can be biased sometimes, I buy the magazine and regularly can't believe what I'm reading. My own opinion is that they review for money, they slated that Thermalright Ultra and said it wasn't value for money when its the best cooler around, it just lacks a fan, I'd like to add my own anyways. They fail to state that the Tuniq Tower (which I have) won't fit alot of cases as its too big. Point being, take all review sites with a pinch of salt, better off reading forums for proper reviews.

You can't go wrong with the freezer pro, its recommended here alot as its a good cooler that won't break the bank.

CrinkElite

PogMoThoin wrote: »

Custom PC reviews can be biased sometimes, I buy the magazine and regularly can't believe what I'm reading. My own opinion is that they review for money, they slated that Thermalright Ultra and said it wasn't value for money when its the best cooler around, it just lacks a fan, I'd like to add my own anyways. They fail to state that the Tuniq Tower (which I have) won't fit alot of cases as its too big. Point being, take all review sites with a pinch of salt, better off reading forums for proper reviews.

You can't go wrong with the freezer pro, its recommended here alot as its a good cooler that won't break the bank.

gotchya, goin with the freezer, thanks a bunch:D

TerrorFirmer

I wouldn't say the Arctic Freezer would struggle exactly with a quad at 3Ghz, more so it would produce temperatures far higher then what it would yield with dual core, but still nowhere near the danger or even warning threshold. I had my quad at 3.2Ghz with the stock Intel cooler, for example - temps weren't great, but entirely functional and not a real problem. Of greater concern in these sort of scenarios would be more so what the airflow in your case is like, fans, size of case, etc. I also had my quad with the Akasa Arctic Freezer clone, and temps were quite good at 3.2Ghz.

Solitaire

^ +1. Again. :rolleyes:

Nothing wrong with a reliable 92mm cooler (Akasa AK965, AS Freezer 7, OCZ Vanquisher if you lap it first!!) on a quad up to ~3.33GHz, after which it all goes a bit pear-shaped. That said, in an old Techgage roundup those coolers listed above kept a old 125W+ QX6850 OCd to 3.67GHz below throttling threshold where a lot of 120mm power towers failed epically - not really good for everyday use but they kept it alive against great advesity

CrinkElite

nic, anythings gotta be better than the temps I have at the moment in any case [60C on idle and up to 76 on load until i sh1t myself and stop the intel TAT test]

I realise these are not normal for a e6600 @ stock 2.4 Ghz.

I figure seeing as I'm gonna have to refit the stock cooler I may as well pick up something cheep and cheerful to throw on there instead of putting it back on.

I didn't build it myself as it was my first machine (shame) and the guys who did a a bunch of twats <ahem> ankermann.

Solitaire

If you're testing with Linpack/TAT bear in mind its an industrial-scale test (actually based on Intel's internal test suite) and will significantly exceed any other torture test in terms of stability, heat and power requirement. Realworld usage will never even approach it which is why Orthos/SP95 is still the preferred torture test (TAT is literally overkill and for bragging rights only! )

No idea how you're managing that idle temp though. Something is desperately amiss there! :eek: Is the cooler properly seated? And how good is your case? A good cooler is useless in a case made of fail. Although I doubt a good cooler would even fit in such a case in the first place :P Smaller cases can barely fit 92mm towers :rolleyes: