T3400 spread spectrum clock

Question

Hello,

I need to insert PCIe card to Precision T3400. To work with PCIe card, It is needed to turn off spread spectrum clock (SSC) on mother board. How can I turn off SSC on Precision T3400 ?

Best regards

speedstep · Accepted Answer

@Minh Truong

Please press the blue Accept as Solution button below if this post answers your question.

Equipment legally sold in the US must be validated for FCC part 15 regulations.

I am not the FCC. I do not answer questions for every PC in the USA. CFR (Code of Federal Regulations) The U.S. Code (U.S.C.) is the compilation of federal laws.

FCC CFR 47 Part 15 – Radio Frequency Devices
FCC CFR 47 Part 18 – Industrial, scientific, and medical equipment
FCC 15.107 – Conducted limits.
FCC 15.109 – Radiated emission limits.
FCC 15.209 – Radiated emission limits; general requirements.
FCC 15.217 – Operation in the band 160-190 kHz.
FCC 15.219 – Operation in the band 510-1705 kHz.
FCC 15.223 – Operation in the band 1.705-10 MHz.
FCC 15.225 – Operation within the band 13.110-14.010 MHz.
FCC 15.227 – Operation within the band 26.96-27.28 MHz.
FCC 15.229 – Operation within the band 40.66-40.70 MHz.
FCC 15.231 – Periodic operation in the band 40.66-40.70 MHz and above 70 MHz.
FCC 15.245 – Operation within the bands 902-928 MHz, 2435-2465 MHz, 5785-5815 MHz, 10500-10550 MHz, and 24075-24175 MHz.
FCC 15.247 – Operation within the bands 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz.
FCC 15.249 – Operation within the bands 902-928 MHz, 2400-2483.5 MHz, 5725-5875 MHZ, and 24.0-24.25 GHz.
FCC 15.407 – General technical requirements.

speedstep · Answer

@Minh Truong

Please press the blue Accept as Solution button below if the post answers your question.

No such PCI-E setting for T3400 or any dell that I know of.

Afaikt SSC is for SATA PHY not PCI-E PHY.

PCI-E 3.X PHY Vs PCI-E 2.X 8b/10b / 128b 130b

https://teledynelecroy.com/doc/spread-spectrum-clocking-and-serial-ata

nbaever3 · Answer

Hello, I have a Dell Precision T3400, I want to disable the spread spectrum clock, But I do not see any setting in BIOS

speedstep · Answer

@nbaever3

Please press the blue Accept as Solution button below if the post answers your question.

No such F2 Bios setting for PCI-E on T3400 or any dell that I know of.

Afaikt spread spectrum clock SSC is for SATA PHY not PCI-E PHY.

PCI-E 3.X PHY Vs PCI-E 2.X 8b/10b / 128b 130b

https://teledynelecroy.com/doc/spread-spectrum-clocking-and-serial-ata

JOcean · Answer

I completely agree with @speedstep , I have never seen such a setting on Dell systems. This web page has a little more information on SSC as does this one and if you do a search for 'turn off spread spectrum clock (SSC) on mother board' you will find a number of articles on the Internet.

speedstep · Answer

@JOcean

Please press the blue Accept as Solution button below if this post answers your question.

Spread spectrum controls are really added to motherboards for one purpose only - they are sometimes needed so that a device for sale within the US can include a legitimate Declaration of Conformity stating compliance with Part 15 of the Federal Communications Commission (FCC) Rules. This stipulates that operation of the device (motherboard), (a) may not cause harmful interference, and (b) must accept any interference received, including interference that may cause undesired operation. Sales of electronic devices within the US require the strict observation of all FCC rules and regulations. There is no overclocking or tweaking of Precision Models in bios so this option is never forthcoming.

https://f2labs.com/fcc-part-15

Minh Truong · Answer

hi @speedstep  Does it mean that every PC at US can not turn on/off SSC ?

Precision Fixed Workstations

T3400 spread spectrum clock

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