R507 Vs R404a - Which Is Better?, Looking to get regassed Options

[Firelord]

Gonna send my prommi off for a service after xmas and was gonna get a regas done at the same time.

So which is better for everyday use r507 or r404a?

I am looking to maintain a similar level quietness I can get at the mo with Mach II as is/was. Do I need to run the fans on turbo all the time or can I get away with manually setting to say 1400rpm?

I know the GT uses r404a so would achieve similar temps.

What mods would need to be done if any to have them gassed?

Cheers

[Rockin]

afaik, the fans need to be set higher than a Mach II. I set min at 1800 front and 1900 back. The temps difference between r404a and r507 is only a couple of degrees which shouldnt see any real life performance difference.

If you want quiet/silence then stick with r134.

TBH after using this water cooled rig @ 2.6ghz, even with the fans @ 7v, this prommi on turbo is almost inaudible next to the water rig.

[Firelord]

I usually just run it without MCC on this machine and this sets fans to 1400 iirc and seems pretty quiet to me.

I like the idea of r507 as may be able to push the 3400 to 2.9Ghz

[Rockin]

Its not just about the gas in it though, its how its modded and set up too.

Im without doubt that this rig would out perform a GT or similar rig, just because of the temps and stability so far seen.

Its a compromise though, i cant run at this and have absolute silence, but i dont care for what i want. I want something thats as fast as is stable.

[Firelord]

Hmmm tough decision.

So what would need to be done other than just a straight gas swap?

[Psykotik]

The unit needs to be tuned for the maximum heatload that your chip will kick out in order to attain optimal performance, and IIRC that involves shortening or lengthening the captube, and/or tuning the charge.

[fattimus]

With R507 you dont need to mod the cap tube you can straight swap the gas some people recomend replacing the filter drier however this is normaly only done after a compresssor burn out if the system hasnt been exposed to the atmosphere for huge amounts of time then it is not required as long as you vac the system out

This post has been edited by fattimus: Dec 15 2004, 07:12 AM

[Trunkey]

I am going to watch this with intrest as I can not get my FX 53 past 3025 stable no matter what volts it has through it. It can only be that my standard prommi can not remove enough heat a these speeds.

[Marci]

r507 can be dropped straight into a regular MachII with no changes other than increasing fanspeed slightly to cope with increased operating pressures. r404 requires a captube mod (addition of 1.5mtrs) to be able to offer the same performance.

r404a on a STOCK Mach II with no cap tube addition will be capable of removing a much higher heatload, in the region of 200w+, however, an FX55 at 1.8v @ 3.4Ghz isn't even pushing out 160w.

If the unit is charged with r404a with no captube change, you'll actually get much worse performance as you don't generate anywhere near the heatload the system is designed for and won't get the super-low temps you'd expect. It'd hover in the -40s at best, with -30ish full load temps. The processors in play today (A64) topout long before the modded prommi tops out. For instance, Rockindave has topped out at 3.4Ghz, as has Pizzaboy... yet evaporating temps are still in the -50s. If the promi had topped out these temps would have rocketed up to -20 (prommi at full heatload is rated at 180w@-20 deg or similar) so the current prob is with the CPU or subsystem (more voltage required etc etc).

If anything, you could possibly get better temps and a higher overclock by lengthening a stock MachII for use with r507 to bring the unit back down to 170w heatload as opposed to it's designed heatload, as that's just above where CPUs are actually topping out. This would produce much lower temps at the speeds these guys are running... eg: You'd possibly see both Pizzaboy and RockinDaveUK at 3.5Ghz if another 10cm of captube was added to their systems (thus reducing the max heatload the unit can handle, but bringing that maximum down closer but still above the maximum that anyone is able to generate at the moment with any CPU on any singlestage system) and then recharged again with r507. This would pull evap temps down another 10 degrees or so, improving stability at 3.4Ghz or allowing for an unstable 3.5Ghz.

Summary: Stick r507 in a stock MachII and leave it at that basically... as soon as you move to r404a you're looking at paying thru the nose BIG TIME for a LOT of tweaking and titting about to get it tuned for the same temps and thus the same performance.

[Firelord]

Thanks ever so much marci very good read May I suggest perhaps whacking that in a sticky cos I bet theres quite a few people in a similar situation!

Looks like a r507 then!

[Marci]

And, I'll copy and paste a post over I jsut made at EP-UK for reference as there are some relevant points in that, as well as the same points I made above... the topic in question here tho is the practicality adn advantages of the baker evap head and what circumstances warrant having one fitted...

Just bear in mind the cost effectiveness of all this... Prommi Mach II Stock gets you on average a 400Mhz increase over regular watercooling (from an Athlon 32 perspective). A regas will get you another 100 to 200Mhz on top of that. A Baker head another 100Mhz on top of that at most. If you already have a regassed system, is it really worth shelling out £200 to have a baker head fitted and then it regassed AGAIN for the sake of another 100Mhz over a straight regas alone.

As I've always said, if you're gonna have it done, have EVERYTHING done at once first time... don't regas then at a later date have a new head fitted etc, as for every option you're paying for a regas again on TOP of the additional items / mods that you want doing. Also, the extra capacity of the baker head and difference in flow resistance means both the captube and the suctionline need fine tuning to attain the same performance as a stock regassed MachII. It's not as simple as take on head off and put the other on. Both cap tube and suction line have to be altered to compensate for the differences between the two heads.

The baker head is more of an option for a replacement for a completely duff head rather than a performance upgrade over a working perfect stock head as the performance increase is very marginal in terms of what you're actually going to see.

If you're running all this on A64 chips, there's also no point whatsoever in shortening captubes for higher heatloads, as you're not getting anywhere near topping out a regassed prommi with a FX55 clocked to it's limits... once you get an A64 up to around 3.5Ghz you're getting as far as you'll EVER get on singlestage phasechange. Any further is going to require cascade.... not because of the wattage it's putting out, but because you also need to pull the temps down dramatically to be stable at that wattage.

For instance... I tune a prommi to 220w heatload at -20 deg C. I stick that prommi on an FX55 at 3.4Ghz, 1.9v. It runs at -55 deg C, but is unstable.

The prommi isn't the problem, the CPU is. The prommi is nowhere near topped out as if it was it'd be at or hotter than -20 deg C. Therefore, the wattage being removed isn't the issue preventing the CPU from going higher. The actual temperature is, and the temperature reading is of no relevance to the amount of wattage being removed.

A good waterkit can remove 300w of heat. A prommi can remove tops 200w of heat. Yet the prommi gives the best overclock... why? Not because of the wattage being removed, that's for sure. It's just a matter of colder = faster. The faster you get the chip, the bigger the temp drop required to get any further. You'd need to drop another 20 or 30 degrees over a standard regassed MachII to get another 100/200Mhz over the 3.4Ghz FX55. You won't get 20 or 30 degrees colder by a refrigerant change, or captube change, or evap head change. You'd have to move to cascade, or COMPLETELY rework the singlestage system with a larger stronger (1/2HP as opposed to 1/3HP) compressor, larger condenser, proper sized aircon fan or 130CFM+ fan (so very noisy), and hipressure relief valve bridging low side to high side... which would have to be manually opened to allow the unit to equalise every time you switch it off unless you were good with electronics and hook it to a solenoid. The other alternative is to abandon captube and use a TXV to give a completely variable wattage removal capacity... just turn the knob.... however, every time you change that knob you'll need to finetune the refrigerant charge.... so only an option if you have all the gear yourself.

Anything other than a straight regas to 507 on a stock MachII simply isn't worth doing unless done by someone who knows EXACTLY what everything needs to be set at, which can only be gained by experience.... LOTS of experience. Bowman etc have 6+ years experience and notes of every unit they've ever done. They can look on a chart and go "need this this this and this, plug it on, gas it like this, done". Anyone else (myself, Fattimus etc) would have to do it, fine tune it, correct it, fine tune it.... round and round again. What would take Bowman a day to do would take MONTHS of experimentation for anyone in the UK to do and get anywhere near as good performance.

A straight regas should be enough for everyone. Head replacement should only be required if the current head has a problem (blocked / damaged). Only other use for a baker head is on a complete custom build.

It's well worth having a stock MachII regassed to r507. Any mods after that simply aren't cost efficient vs the gains you'll get and the time it takes to do it... at a PUSH it's worth recharging a GT with 507 and finetuning the charge only... leave captube and everything else as is... just so it's charged closer to the load you are capable of producing, rather than the load the prommi is capable of handling, as that will get you better temps.

That's my opinion anyways...