Editing RDRAM (section)

===Performance===
Compared to other contemporary standards, Rambus showed an increase in latency, heat output, manufacturing complexity, and cost. Because of more complex interface circuitry and increased number of memory banks, RDRAM die size was larger than that of contemporary SDRAM chips, resulting in a 10&ndash;20% price premium at 16&nbsp;Mbit densities (adding about a 5% penalty at 64&nbsp;Mbit).<ref>{{cite web |url=http://www.findarticles.com/p/articles/mi_m0EKF/is_n2161_v43/ai_19288320 |title=Electronic News: Rambus seeks IPO but denies Intel stake - Company Financial Information |website=www.findarticles.com |access-date=12 January 2022 |archive-url=https://web.archive.org/web/20041124045440/http://www.findarticles.com/p/articles/mi_m0EKF/is_n2161_v43/ai_19288320 |archive-date=24 November 2004 |url-status=dead}}</ref> Note that the most common RDRAM densities are 128&nbsp;Mbit and 256&nbsp;Mbit.

PC-800 RDRAM operated with a latency of 45&nbsp;[[nanosecond|ns]], more than that of other SDRAM varieties of the time. RDRAM memory chips also put out significantly more heat than SDRAM chips, necessitating [[heatsink|heatspreaders]] on all RIMM devices. RDRAM includes additional circuitry (such as packet demultiplexers) on each chip, increasing manufacturing complexity compared to SDRAM. RDRAM was also up to four times more expensive than PC-133 SDRAM due to a combination of higher manufacturing costs and high license fees.{{Citation needed|date=May 2016}} PC-2100 [[DDR SDRAM]], introduced in 2000, operated with a clock rate of 133&nbsp;MHz and delivered 2100&nbsp;MB/s over a 64-bit bus using a 184-pin DIMM form factor.

With the introduction of the Intel 840 (Pentium&nbsp;III), [[Intel&nbsp;850]] (Pentium&nbsp;4), Intel&nbsp;860 (Pentium&nbsp;4 Xeon) chipsets, Intel added support for dual-channel PC-800 RDRAM, doubling bandwidth to 3200&nbsp;MB/s by increasing the bus width to 32&nbsp;bits. This was followed in 2002 by the Intel 850E chipset, which introduced PC-1066 RDRAM, increasing total dual-channel bandwidth to 4200&nbsp;MB/s. In 2002, Intel released the E7205 Granite Bay chipset, which introduced dual-channel DDR support (for a total bandwidth of 4200&nbsp;MB/s) at a slightly lower latency than competing RDRAM. The bandwidth of Granite Bay matched that of the i850E chipset using PC-1066 DRDRAM with considerably lower latency.

To achieve RDRAM's 800&nbsp;MHz clock rate, the memory module runs on a 16-bit bus instead of a 64-bit bus in contemporary SDRAM DIMM. At the time of the Intel&nbsp;820 launch some RDRAM modules operated at rates less than 800&nbsp;MHz.