PSU 650w or 750w? help me to decide

okay, 650w is the sweet number, 750w is still overkill then?

so with RMi 650w I will get the ideal 50% on full load then? 450 is like 70% of 650. wouldn't want the PSU runs on high percentage for a long time

about that 50%, maybe I phrased it badly, sorry. it's 50% of PSU capacity or PSU load where PSU runs most efficient, as you elaborated above

maybe this post phrasing it better:
http://www.jonnyguru.com/forums/showpost.php?p=125738&postcount=20

"having said that, i would get something beefier so avoid running the PSU at such a high capacity. you want to stay at around 50% of the PSUs capacity at high work load. that's when a PSU is most efficient, runs coolest, and reduces wear on components. another bonus is that it's always dead silent because the PSU fan never turns on. so i would aim for a 650W - 700W PSU."

"at 50% load (around 600W) the PSU is extremely efficient and runs very cool because of it. i also never have to worry about wearing it out. "

okay, looking good on 650w. just need one more push hehe. tough customer hard to be convinced, sorry. hard earned money want everything to be perfect, the usual wishful thinking

so I look at these:
Cold Test
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story3&reid=445
Hot Test
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story4&reid=445

idle at 150w would be around Test#2 but slightly higher, full tilt at 450w would be around Test#4 but a tad lower, both Cold and Hot efficiency are around 89-90% in those tables. that's... good, right? I know efficiency goes down on low load. I just thought 50% load is the ideal number full tilt should stay at, but since you wrote 90% still okay, maybe you're right. as long as not 100% coz that'll wear down the PSU quick which we want to avoid along with high temp which important to me coz tropic sucks. and of corz full load won't happen continuously but rather goes up and down depends on what I'm doing. also I live in Asia where the AC current is 230V, read somewhere that efficiency will be even more efficient on 230V than North American 120V (or 112V?). or I read it wrong

there's 550w on RMx, but RMx doesn't have fan test button which will drive me crazy since I'm a paranoid. I can live without C-Link though I'd very much love to control the fan manually coz it's hot tropical over here, being able to peek various power stats is a welcomed bonus. and RMi has that multi-rails which I want, RMx only single

thanks for keep answering

hey guys, sorry for the late reply. my ISP suddenly died for whole day. really annoying. thanks for keep replying. really appreciate it. I just realized I gave both Cold Test link for the links above lol. I've fixed the Hot Testing link above

okay, as you said the efficiency fluctuation is rather flat in RM650i, only about 1%, as shown by the links above. well, 5% on Test#1 (below 70w) and Cross Load 1, but I don't think my PC will ever run on such wattage. and I don't really understand what Cross Load mean

okay, as you said, efficiency is not a problem with good PSU such as this one

my other thoughts on why keep PSU max load at 50% are:
- to keep the temp on decent level (tropical here, so temp is always a problem). isn't making the PSU always loads at high 90-100% in a long time, means temp is also raking up?
- to reduces the speed of PSU component wearing up. if PSU always works at high load, which produces high temp along with it, that means PSU wears down faster, right?

yeah, I know the load actually doesn't stay at certain percentage for too long, it fluctuates. though it'll be nice that at certain period of time on an average rate it'll stay at not too high percentage, lets just say it averagely "stays" around 50-70% maybe for most of the time, with some little curves 80-90% on the PC max load

I know I'm being uh... looking too far in problems the usual human's wishful thinking for eternal usage lol. spend money once, put it in and forget, hope it'll work flawless for 20yrs. it's Tier 1, I expect miracle! the usual "wanna be safe" type asking too many dumb questions lol

okay then. RM650i for me then. too bad there's no 550w (or 600w, why 50w more/less) for RMi. I think I don't want RMx, it doesn't have fan test button which will drive me crazy and single-rail rail only. about the warranty, there are some contradictory info on this one in my country, one seller said 5yrs, the other one wrote 7yrs. I know it should be 10yrs worldwide as Corsair stated in their site. gotta call the distributor later for better info (there's only one official Corsair distributor in my country), hopefully it's 10yrs too in my country like everywhere else... why my country always gets the end of the stick...

hope this one will running cool. my current CX600 is pretty hot on high load, I can feel the heat radiating from it and the case to my hand at 5cm distance. yeah, I know CX600... Tier 3, sucks?

thanks for helping me in reaching this decision, Rogue Leader (especially you), mrmez, and turkey3_scratch

yup, one RM650i for me. good PSU this one. btw hope you're still there, forgot to ask 2 questions regarding Corsair Rmi

1. RMi's 12V rail cable for the GPU is the branching style, I mean, one cable with 2 GPU 8-pin connectors branching out in the other end. this maybe yet another dumb question but it's fine of course to use this one cable only on my GTX 970, right? on my current CX600 (non modular), one cable has one GPU connector only, so I have to connect two cables, each to the GPU female power connectors, one-on-one. but I believe RMi has more than enough power on its 12v rail (40amp I read, on multi rails setting), and using one cable with branching 2 connectors will produce the same power output as, for example, using two cables where the end to the PSU connected to each different 12v connector on the PSU, and the end to the GPU using only one connector of the branch connected to each one of the GPU power female connectors, i.e. two cables each connected to each of GPU power connectors. using one cable to handle all GPU power connectors sure is better for cable management. and if using one cable is the same as using separated two cables, or in other words: using two separated cables from separated 12v connectors on the PSU has no different/beneficial effect to use one cable (doesn't mean more power or more stable etc.). why use two cables then, if there's no any merit?

2. I have a simulated sine wave UPS, if I later test RMi on it while on battery mode and it works (PC still on, not immediately shutdown), then... this means it's good, right? both PSU and UPS are compatible working together. while the main AC power is working (through the UPS), it won't damage the PSU or anything, right? and even if the power runs through the batteries (in instance of blackout), it won't do any damage the PSU, right? (provided the PSU works on the UPS battery mode, not shutdown on the 1st place)

my CX600 works with my UPS on battery mode. when blackout occurs, the UPS switches to battery power, my PC is still on, giving me enough time to shutdown my PC properly. this means CX600 works with my UPS, right?

I just found out about pure sine wave thing, and been Googling about whether APFC PSU + simulated sine wave UPS combo is a bad thing. I'm wondering if my PC recent intermittent freezes are related to this or not. while in the end I still couldn't find the absolute answer whether it's bad or not, from what I gathered, the problem seems only lies on the APFC circuit thing, there are PSUs with sensitive APFC circuit, and when paired with simulated wave UPS, it'll immediately shutdown on the UPS battery mode, i.e. not working with the UPS. why bother to use an UPS on the 1st place if one can't do a safe shutdown on blackout, right?

but if the PSU still on when on battery mode, then congratulations, that's that. right? no harm done using the PSU with the UPS, right? still can't get clear fact whether even if it works, the simulated wave will slowly break the PSU? slowly and silently but sure the PSU is gradually dying? and if it is, does it only slowly breaks the PSU while in the battery mode, or it'll break the PSU even on main AC power running? is my UPS slowly breaks my CX600, and finally after some time, the CX600 finally dying, and makes my PC randomly freezes. or this freezes are actually not the PSU fault, but something else. the freezes have occurred on the 1st day of purchase though, since new mobo+CPU+RAM came in, all hell breaks loose. been using the CX600+the simulated wave UPS for 2 years with older mobo+CPU+RAM, zero problem

Someone also said that simulated wave is indeed harmful to the APFC circuit (thus breaks whole PSU eventually if this circuit breaks), so when a blackout occurs and the PSU is running from the UPS battery power, do not dillydallying in shutting down one's PC. as long as one doesn't run the PSU on the UPS battery power more than 5 minutes, the APFC circuit will not get strained, it'll be okay, no harmful effect on it, as long as no more than 5 mins. the golden rule: not more than 5 mins, shutdown your PC quickly. I think I can do that

I really don't want to spend more money on pure sine wave UPS is it's not really necessary, they're really expensive here, not to mention replacing the batteries are so much hassle in my country (official batteries cost an arm and a leg, so have to use alternative solutions which is... a hassle). thanks for the attention

okay, thanks for the answers. got it, one cable is fine. and got it, it's all about the APFC circuit whether it's being fussy, likes the wave or not. if not, shuts down, if yes, congrats, resume usage, no harmful effect whatsoever to the PSU nor the APFC circuit. I also read some PSUs (some Seasonics?) will still work with simulated wave as long as the watt load doesn't exceed certain level (usually high PSU load) regardless the UPS watt capacity is more than enough. not sure on how I feel about this

so when I test the RMi later with my UPS, pulled the UPS plug out of the wall, and my PC is still on just like my current CX600, then congrats myself. no any harmful effect to the RMi PSU when using it with the UPS, main power or battery. this is what concerns me most as there are conflicting info on this, some say yes it will be harmful, some says nope, that's just FUD and scare tactic from the marketing so you'll waste more money to buy more expensive UPS

makes me wonder now, maybe my CX600 is still fine after all, the culprit of the intermittent freezes is something else. or maybe the CX600 is indeed just dying slowly coz it suck quality itself, got nothing to do with the UPS at all

well, if the PC shuts down, I must spend more money for true sine wave UPS... lets hope for the best

thanks for the replies as always

hello, sir

I'm so disappointed right now. my local Corsair distro told me to wait for two months for the new shipment of RM650i, since 2 months ago when I asked about it, no stock. so I waited for 2 months, and it's still not available lol. I think RMi series won't be here ever. this country of mine, not many PC enthusiasts, well, there are some filthy rich elitists who buy expensive high-end stuffs, which is why there are still some leftovers of RMi/HXi/AXi 850w-1200w which I'm as a mid-end user don't need. in the other end, we only have low-end users, but they make the big percentage of purchase, so PC selling business here are focused on low ends. not a good place for a mid-end guy like me. don't want stay low-end but don't want to sell my kidney to stay in the highest end. not many choice for the mid guy

okay, I'm sick of waiting, why can't they just say it straight into my face, "nope, RMi is such unpopular series in this country we won't ship one just for one guy." I know, business ethics told em to always say, "I'm very sorry, at the moment there's no stock. Please comeback later, who knows... ". so since everyone who know their stuffs I asked, everyone says 550w is the best number for my needs and the next future, as long as I follow what I wrote on the 1st post about upgrading.

I'll get RM550x then, no other choice. RM550x seems very popular over here, the peak of the low-ends. I read reviews about RM550x, while I don't understand most of the technical stuffs, and usually just skip to conclusions, I think it's a decent PSU. not many differences from RMi:
- I'll try to live with no fan test button
- really don't care about Corsair Link honestly
- I don't mind about the lower fan quality, TBH I can't hear anything from my CX600 fan, and I don't know what fan it uses

well, the single-rail only... nothing to be worried about, right? sometimes I can be such a paranoid... okay, my CX600 is single rail, nothing has explode yet in these 3 years, so it'll be fine

RM550x is a good PSU, right? perfect my need and the next future upgrade

thanks. feeling stupid waiting for 2 months lol

thanks for the reply

okay, will ask them about RM550x, if this one also no stock... lol. though on some local store websites, they wrote, "new, recommended best PSU for single 1070/1080". new huh... very late coming in here. hope there are still many available
also just read Tom's Hardware review about this PSU, so the fan spins for a while before stopping every time I power on the PC, good then, at least I can see whether it works or not

yesterday I also asked about Corsair Carbide 400C black, no stock too lol. just my luck. but the white one is marked "newly arrived" in local store websites. okay, white, I don't mind, I'll as this along with RM550x hope there are still some available

alright then. wish me luck and thank you for your patience always. will report back for the last time after I get my hands on the stuff