What is Refclk in PCIe?
2 PCIe Reference Clock Typically, PCIe REFCLK is used to derive the local clock. PCIe REFCLK is specified as a 100 MHz (PCIe 1.0 -PCIe 4.0: +/- 300 ppm, PCIe 5.0 – PCIe 6.0: +/-100 ppm) clock using an HCSL signal logic. Another important consideration is the jitter performance of the REFCLK.
What is Ref CLK?
The Common Refclk Rx architecture is the easiest and most commonly used method for clock distribution among PCIe devices. The Common Refclk Rx architecture has the filtering of the receiver clock multiplier PLL (Rx PLL in Figure 4-89 of PCIe 3.0), but the Data Clocked Rx architecture does not.
What is PCIe clock in BIOS?
This is where the PCI-E Reference Clock BIOS option comes in. It controls the frequency of the PCI Express reference clock. By default, the PCI-E Reference Clock is set to 100 MHz. This is the official reference clock speed for the PCI Express interface.
What is reference clock in PCIe?
The PCIe Serializer De−serializer (SerDes) system uses a reference clock (Refclk) to generate higher frequency clock from internal PLL which delivers higher bit rates. Typically the reference clock is multiplied by 4 to 25 times to generate the bit rate frequency.
What is SSC in PCIe?
Spread Spectrum Clocking (SSC) is a highly effective technique utilized to reduce electromagnetic interference or EMI. PCI Express 5.0 System designers use this tool to reduce the adverse effects on adjacent circuits and to pass FCC or other regulatory body requirements for EMI emissions.
What should my PCIe frequency be?
Overclockers, generally try to set the PCIe frequency between 101-120 MHz. The higher you go, the more the effects you will see.
What is the best PCI latency timer?
Normally, the PCI Latency Timer is set to 32 cycles. For better PCI performance, a longer latency should be used. Try increasing it to 64 cycles or even 128 cycles. The optimal value for every system is different.
What is Hcsl?
High Speed Current Steering Logic (HCSL) is the de facto output types for PCI Express applications and Intel chipsets. It is an open emitter output with a 15mA current source and requiring 50Ω external resistor to ground for the output to be switching.
What is PCI speed?
PCI is a 64-bit bus, though it is usually implemented as a 32-bit bus, and it can run at clock speeds of 33 or 66 MHz. At 32-bits and 33 MHz, it yields a throughput rate of 133 MBps (at 66 MHz 266 MBps). The vast majority of today’s PCs implement a PCI bus that runs at a maximum speed of 33 MHz.
What is PCI bandwidth?
Bandwidth. The amount of data that can be transmitted over a PCI-X bus, otherwise known as the bus’s bandwidth, is limited by the size of the physical bus and the speed at which it runs. Most PCI-X buses are 64-bits and run at either 100MHz or 133MHz, allowing for a maximum transmission speed of 1,066 MB per second.
What is the bandwidth of PCI Express?
PCI Express 3.0 uses an 8 GT/s bit rate, enabling a bandwidth capacity of 1 GB/s per lane. Accordingly, a 16-lane graphics card slot will have a bandwidth capacity of up to 16 GB/s.