DDR5 SDRAM was introduced in 2021 and brings many performance enhancements, but just how much faster is it over DDR4? And how does it compare to other memory types like HBM2e and GDDR6?
The simple way of comparing DDR5 versus DDR4 is to say that it’s twice the bandwidth. However, such a broad statement doesn’t capture the real-world variety of factors, including module speeds anwd number of modules in the system (four DDR4 modules may provide similar performance to two DDR5 DIMMs for example).
Across the five generations of DDR, module performance is usually stated either in MT/s (mega transfers per second) or GB/s (gigabytes per second). The clock rate is half of the data transfer rate, which is where the ‘double data rate’ comes from in the DDR acronym. This ratio hasn’t changed with DDR5.
What has changed is a significant increase in the transfer speeds (MT/s or GB/s) available. Today’s DDR4 has reached speeds of 3200 MT/s @ 1,6 GHz clock rate for ECC modules; modules are usually stated with the specific module speed, so this would be DDR4-3200. But for DDR5, Altron Arrow is already offering a DDR5-5600 option for FPGA-attached SDRAM – that’s 5600 MT/s @ 2,8 GHz.
Dual versus single channel
Shifting from DDR4, there is a notable change in the number of channels per module, as DDR5 DIMMs are now dual channel. Those channels have smaller bus widths that generally negate the raw bandwidth advantage one might expect here. Specifically, for DDR5, each module has two 40-bit channels, with eight of those bits for ECC. Therefore, on a module level, that’s 80 bits total, compared to DDR4’s single channel of 72 bits (including 8 bits for ECC).
With 80 bits versus 72, DDR5 does have a slight advantage if the user is turning those ECC bits into ‘regular’ data bits. If ECC is not being used for regular data, then the two are essentially the same: 64 bits single channel or 64 bits spread over two channels.
However, when compared to the high-end memory types like GDDR6 and HBM, has DDR5 bridged the significant gap in performance?
Figure 1 shows a significant increase in speed over DDR4, but this pales in comparison to the performance increases when looking at GDDR6 and HBM. Although not quite as fast as HBM2e, GDDR6 and HBM still outperform DDR5 by a 10x order of magnitude. GDDR6 supports two independent 16-bit channels per bank, so a card with eight banks of GDDR6 has up to 448 GB/s of available bandwidth.
Intelligent video processing Rugged Interconnect Technologies
Computer/Embedded Technology
The CHARM150AGX is based on a NVIDIA AGX Orin embedded processor, which incorporates a multicore ARM processor and powerful AI/ML accelerator.
Read more...Nordic expands nRF Cloud with firmware vulnerability scanning RF Design
Computer/Embedded Technology
nRF Cloud identifies vulnerabilities in firmware and shows exactly which deployed devices are affected, empowering device manufacturers to address EU Cyber Resilience Act requirements.
Read more...Arrival of the Epic-PTH9 Vepac Electronics
Computer/Embedded Technology
AAEON introduces the EPIC-PTH9, a compact 4-inch industrial single-board computer powered by Intel Core Ultra Series 3 (formerly Panther Lake) processors.
Read more...An industry-first Android 16 smart module solution RF Design
Computer/Embedded Technology Telecoms, Datacoms, Wireless, IoT
The MeiG Smart SLM580 4G Smart Module features native support for Android 16 and covers core frequency bands in major countries and regions worldwide.
Read more...MIKROE celebrates 2000th Click board
Computer/Embedded Technology
MIKROE has launched its 2000th Click board, the RTC 27 Click, designed for low-power real-time clock and calendar functionality, time tracking, alarm event generation, watchdog timing, and timestamp capture.
While every effort has been made to ensure the accuracy of the information contained herein, the publisher and its agents cannot be held responsible for any errors contained, or any loss incurred as a result. Articles published do not necessarily reflect the views of the publishers. The editor reserves the right to alter or cut copy. Articles submitted are deemed to have been cleared for publication. Advertisements and company contact details are published as provided by the advertiser. Technews Publishing (Pty) Ltd cannot be held responsible for the accuracy or veracity of supplied material.
Figure 1. Comparison between DDR, GDDR and HBM (courtesy of bittware.com).
printer friendly version