This is probably no surprise but Jailbreaking will slowdown the responsiveness of the iphone's OS.

I jailbreak dozens of iphones for friends over here.

and I'm noticing a pattern. first off let me state the testing facts. I'm jailbreaking only, not unlocking, and not installing any apps. its just a plain restore then a quickpwn, nothing else. I set autolock to never and have no wifi or edge connection.

I jailbreak 2G and 3G and have a non jailbroken, 2G and 3g iphone freshly restored. i setup all iphopnes identical in settings and what not, all fully charged, all with same firmware.

I put them side by side and clearly I see a difference. I use a stop watch for each iphone.
a JB 2.0, 2.1 and 2.2 iphone does not run as fast as the non JB one. I use a stop watch to measure the speed and clearly I can see a pattern.

I test unlocking screen, opening up SMS (tapping letters on keyboard too), settings, calculator, phone, contacts, camera and notes. I do not open anything that requires internet. idea being is to solely rely on apps that do not need more data from outside.

the test is purely to guage speed in opening up apps. First thing I notice is SMS is slow to open up and when tapping on keyboard there is a slight lag delay in letters popping up. this does not happen on a non JB iphone.

once I saw the facts then I loaded some more items, like the must have stuff, OPenssh, sbsettings- which loads mobilesubstrate. mobile substrate caused several times the iphone to go into safe mode, does not seem entirely stable.

once I loaded winterboard with one theme, I clearly saw more lag. and the more I loaded the more lag I could see.

so it seems jailbreaking the iphone does lower its performance which is why i can see the app store rejected sauriks winterboard, customize and other such apps. they indeed do slow down the iphone.

but whats conerning is, of the dozens of iphones I have jailbroken every single person has given me feedback that their iphone is indeed slower than when it was not jailbroken.


how many of you notice this?
after you jailbreak your iphone it is not as fast as when it was not?

most people who I've have JB their iphone, about 50% live with it because they prefer the JB features, the rest simply restored and were happier with the performance boost over JB.

will there ever be a jailbreak method that does not slow down the iphone?
I dont think I've yet publicly seen the dev team aknowledge this problem yet.

I'm pretty confident in my research simply because of the large access I have to iphones. Currently I have jailbroken over 300 iphones and I'm positive in this performance pattern I'm seeing. now don't get me wrong I love jailbreaking and the efforts the dev team have done but I'm hoping something can be done to improve on the lag. My dream is to see a jailbreak that causes no lag at all, basically making it undistinguishable.

to date, every single iphone I've compared, one can always see the jailbroen iphone is a tad slower and if its heavily modded, down right slow at times, like 4 to 5 seconds to open up SMS and simply sliding to unlock.

I have one jailbroken and one 100% "legal" and I can't see any difference.

in my testing I did notice sometimes ( i would say less than 10%) there was no lag on a freshly restored 2.2 and a JB 2.2 but only if nothing was loaded.

the moment I started adding winterboard, themes and stuff like that, it became obvious.
and for all tests I always rebooted the devices to give them a fresh start.

Not Jailbreak is slowing down our iPhones - the reason are the packages that we install from Cydia, like WinterBoard, IntelliScreen, etc.

agreed, winterboard and intelliscreen are to very big culprits.
but in my comparison tests (round 1), those two were not installed and there was a minimal slowdown.
given its in the milliseconds, one can not dispute there is a slowdown after only doing a jailbreak and nothing else.

but after installing some apps from cydia it becomes extrmely apparent..its slows things down in the seconds. the more customizations or apps you add and the more usage of mobilesubtrate the more the slowdown. I believe everyone can agree with this known fact. this is nothign new.

personally the evidence is overwhelimg for me. I've tested this on the 8gb, 16gb 2G iphones, and 3G iphones.

please remember my main emphasis is purely taking iphones that have been restored to said firmware then using quickpwn and nothing else. on first round of tests nothing else was installed from cydia, its just a restore on a 2G and 3G iphone, used this as a control. then took 2G and 3G iphones, restored and jailbroke it. put them side by side with a stopwatch to compare load times. the jailbroken ones 90% of the time displayed lag (took longer).

for grims, after all tests were completed then I went ahead and installed winterboard, mobilesubstrate which is used by several popular apps, and i did also try intelliscreen but that thing is so unstable i found it was best to avoid because it really slowed down my tests, several times it caused safe mode. I wanted to see just how much more I could cause it too lag.

I do see the performance decrease but you have to know it comes with the territory.

I really close to jail breaking my mothers iPhone so I can enable some options that I think she could use. The only thing stopping me is that I don't want her to have stability or performance issues since she lives 3 hours away. She really wants a video recorder.

You have to expect somewhat performance degrade since you have other services running now. Its just bound to happen. All hacks are not created equal or perfect.

Beware of stuff like the BSD Subsystem and daemons in it like ssh. If you install these it will eat up cpu time and memory and slow down. Everything daemonized will do so too, winterboard and other were named here too, there are plenty of others.
Appstore Apps are not allowed to run as daemon or otherwise in background, so they won't do anything like that.

good point sam.
but keep in mind SSH can be turned off. i use sb settings to disablwe ssh and that stops the daemon form running in the background.

what is concerning is even before all this gets install. with just a jailbreak it already slows it down.

does jailbreaking install daemons and hidden processes that run in the background?
on 1.14 there used to be an app called sysinfo that would show you all threads running in bavkground but since 2.x I've not seen an actual app that shows what is running in the background.

perhaps I could retest to see whats running on a JB iphone.

when I say restest, i wish ti be specific in that its only Jailbreak, this not does include installing anything from cydia, nothing.

with nothing else installed my tests already show a decrease in performance.

its been well known installign cydia apps especially those with daemon processes will slow down, as this is the anture of the beast and I clearly acknowledge this.

however I"m trying to prove that the jailbreak process in of itself already does indeed slow down the iphone adn if we can figure out why maybe the code can be refined. but I'll need hard facts to narrow it down.

I haven't noticed any speedy loss both on my 3G & 2G unit

I only notice slowness over time. A "fresh installed" firmware version always feels quicker, but over time (sometimes after 2 or 3 weeks) i notice that everything just opens slower and slower. Only after a new installation of the same firmware + jailbreak it is quicker. Strange behavior, it almost looks like a windows computer is this behavior.