The iPhone's multitasking drawer contains a playback widget for controlling audio apps. Photo: Jon Snyder/Wired.com

The next operating system upgrade for the iPhone, iPod Touch and iPad is landing sometime this week, and customers can look forward to major improvements in Safari performance and AirPlay media streaming.

Wired.com reported on most of the changes in iOS 4.3 when the beta released January. The newest additions that Apple announced last week included a significant speed boost to the Safari web browser, using the new Nitro JavaScript engine, which should make JavaScript run twice as fast.

Additionally, the AirPlay streaming feature has been expanded so that you can stream video played inside Safari or a third-party app to an Apple TV. Previously, AirPlay video streaming was limited to the Videos app on the iPad.

Wired.com got an early look at the iOS 4.3 gold master (usually the official version that ships), and it’s pretty slick.

Benchmark tests Wired.com ran using SunSpider showed a significant speed boost in Safari’s JavaScript performance between iOS 4.2 and iOS 4.3.

An iPhone 4 running iOS 4.3 completed the test in 4,340 milliseconds, and an iPhone 4 running iOS 4.2 completed the same test in 10,626.4 milliseconds (fewer milliseconds is better). That makes iOS 4.3 about 59 percent faster than iOS 4.2 with JavaScript rendering. (See below the jump for the full benchmark results.)

So when iOS 4.3 ships this week, iPad 2 owners won’t be the only people getting a big speed boost. A significant increase in JavaScript performance means web browsing on JavaScript-heavy sites such as Google’s mobile apps (Voice, Docs and Reader), Facebook and others should be zippier.

As for AirPlay, I used an iPhone 4 to play a YouTube video and was able to hit the AirPlay button to send it to straight to the Apple TV 2. Being able to AirPlay YouTube is pretty nifty, because using the Apple TV’s remote control to browse YouTube is a huge pain in the rear; it’s much easier to search for YouTube clips using the iPhone. iOS 4.3’s expanded AirPlay support will be a nice addition for anyone with the new Apple TV.

The iOS 4.3 is due out sometime this week, possibly as soon as Wednesday, according to well-sourced Apple blogger Jim Dalrymple.

SunSpider results on iOS 4.2
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RESULTS (means and 95% confidence intervals)
——————————————–
Total: 10626.4ms +/- 6.8%
——————————————–

3d: 1437.6ms +/- 6.8%
cube: 443.0ms +/- 14.8%
morph: 534.6ms +/- 5.3%
raytrace: 460.0ms +/- 2.0%

access: 1635.8ms +/- 33.6%
binary-trees: 146.2ms +/- 5.8%
fannkuch: 671.2ms +/- 0.6%
nbody: 429.6ms +/- 32.4%
nsieve: 388.8ms +/- 106.4%

bitops: 877.0ms +/- 0.5%
3bit-bits-in-byte: 180.8ms +/- 0.8%
bits-in-byte: 185.2ms +/- 2.7%
bitwise-and: 163.2ms +/- 0.6%
nsieve-bits: 347.8ms +/- 0.5%

controlflow: 143.0ms +/- 1.1%
recursive: 143.0ms +/- 1.1%

crypto: 643.6ms +/- 2.9%
aes: 295.0ms +/- 2.8%
md5: 163.6ms +/- 1.2%
sha1: 185.0ms +/- 11.1%

date: 744.8ms +/- 3.3%
format-tofte: 377.2ms +/- 3.5%
format-xparb: 367.6ms +/- 3.1%

math: 1134.6ms +/- 0.9%
cordic: 425.6ms +/- 1.7%
partial-sums: 372.0ms +/- 0.6%
spectral-norm: 337.0ms +/- 2.6%

regexp: 1444.8ms +/- 1.1%
dna: 1444.8ms +/- 1.1%

string: 2565.2ms +/- 21.6%
base64: 355.8ms +/- 4.3%
fasta: 422.0ms +/- 15.0%
tagcloud: 458.6ms +/- 18.8%
unpack-code: 744.8ms +/- 5.6%
validate-input: 584.0ms +/- 70.2%

====

SunSpider results on iOS 4.3

============================================
RESULTS (means and 95% confidence intervals)
——————————————–
Total: 4340.1ms +/- 0.7%
——————————————–

3d: 557.6ms +/- 1.6%
cube: 213.5ms +/- 3.4%
morph: 136.0ms +/- 0.9%
raytrace: 208.1ms +/- 0.7%

access: 497.2ms +/- 2.4%
binary-trees: 122.2ms +/- 3.3%
fannkuch: 138.7ms +/- 3.0%
nbody: 164.2ms +/- 4.7%
nsieve: 72.1ms +/- 2.1%

bitops: 219.2ms +/- 2.2%
3bit-bits-in-byte: 28.9ms +/- 10.4%
bits-in-byte: 53.6ms +/- 2.3%
bitwise-and: 64.5ms +/- 3.3%
nsieve-bits: 72.2ms +/- 2.3%

controlflow: 25.7ms +/- 4.4%
recursive: 25.7ms +/- 4.4%

crypto: 246.7ms +/- 0.5%
aes: 147.1ms +/- 0.4%
md5: 58.5ms +/- 1.7%
sha1: 41.1ms +/- 2.2%

date: 588.8ms +/- 4.2%
format-tofte: 277.3ms +/- 0.9%
format-xparb: 311.5ms +/- 7.2%

math: 462.2ms +/- 1.1%
cordic: 167.2ms +/- 0.8%
partial-sums: 206.6ms +/- 2.8%
spectral-norm: 88.4ms +/- 1.2%

regexp: 115.4ms +/- 3.5%
dna: 115.4ms +/- 3.5%

string: 1627.3ms +/- 0.9%
base64: 226.3ms +/- 3.2%
fasta: 227.8ms +/- 0.8%
tagcloud: 310.8ms +/- 0.8%
unpack-code: 554.2ms +/- 0.3%
validate-input: 308.2ms +/- 1.9%