The Intel Pentium 4 HT 661 was a desktop processor with 1 core, launched in January 2006, at an MSRP of $401. It is part of the Pentium 4 HT lineup, using the Cedar Mill architecture with Socket 775. Thanks to Intel Hyper-Threading the core-count is effectively doubled, to 2 threads. Pentium 4 HT 661 has 2 MB of L2 cache and operates at 3.6 GHz. Intel is making the Pentium 4 HT 661 on a 65 nm production node using 188 million transistors. The multiplier is locked on Pentium 4 HT 661, which limits its overclocking potential.
With a TDP of 86 W, the Pentium 4 HT 661 consumes a good deal of power, so decent cooling is needed. Intel's processor supports DDR1, DDR2 and DDR3 memory with a dual-channel interface. For communication with other components in the computer, Pentium 4 HT 661 uses a PCI-Express N/A connection. Although the processor doesn't come with integrated graphics, certain motherboards with compatible chipsets can provide this capability. Inside the box you will not only find the processor, but also a D34223-002 ATX cooler.
The SSE4 instruction set is not supported, which can cause problems with modern games, as they require that capability.