
Originally Posted by
Nedjo
I'd guess that this is the secret behind Denebs high overclocability:
The PFET performance improvement is more dramatic with drive current now up to 660 ”A/”m compared with 510 ”A/”m on 65-nm transistors. Again, this increased output current is the result of optimized compressive strain for the p-channel device. The new design of the PFET moves the embedded silicon-germanium source/drain regions closer to the channel to maximize the transfer of stress, thereby increasing hole mobility. Although shorter gate lengths are not driving the improvements, it is a reduction in dimensions that allows increased channel stress to provide the performance scaling. AMD 45-nm PFET design reduces the space from embedded silicon-germanium to the channel edge by half.
The transistor drive current for AMD's 45-nm devices is much lower than that of the Intel HKMG transistors. But power consumption is quickly becoming a high priority for server chips. AMD's transistors exhibit very low channel leakage. Our transistor benchmarks indicates that leakage current is less than one-third of the value measured on AMD's 65-nm process. It's also significantly lower than the Intel 45-nm HKMG process. In fact the Ion/Ioff ratio for AMD's PFET is nearly 10 times better than that for the Intel PFET.
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