Google has commented on our IE8 Beta 1 improvements, and we've made IE8 even faster since then. Some of the tests we have done show pure JScript performance improvements up to 2.5 times. We also measured the performance gains on common Gmail operations, like loading the inbox (34%), opening a conversation (45%) and opening a thread (27%) compared to IE7. Thus far, tweaks to the JScript engine have contributed to improve IE8's performance on the SunSpider benchmarking suite by 400% compared to IE7.
The second area in which we are invested heavily in IE8 is in improvements to our memory usage. To date we have fixed just under 400 separate memory leaks in Internet Explorer. For users, these changes reduce the amount of memory consumed by IE, improve our startup times, speed up navigating between pages, and help IE remain stable for longer periods of time. As we started building IE8 it was clear that we could do more to take advantage of the increasing prevalence of high bandwidth connections. Two key improvements we made with IE8 were to unblock downloads in the presence of external scripts and to increase the number of parallel connections per server that we support.
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