From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nebojsa Trpkovic Subject: FSB overclock & speedstep Date: Mon, 02 Jul 2007 05:38:18 +0200 Message-ID: <4688732A.9060900@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:user-agent:mime-version:to:subject:x-enigmail-version:content-type:content-transfer-encoding; b=tBCUmGR01HdiUV9ETzXyCMbjxqvUM+5sTcxQExlWtB70C4h5HMTrHxNgEg2+LVS8F3JEuBWWmiCXGJKtwe2Za0bn6m3WYGu7tSSKYKOGjrp8KZciVTxz6eSLGIep+W2Bjh8jkFkA7i7z3IUIqAZOc1sxbPzUxQAcebtdyZ3lEkk= List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: cpufreq-bounces@lists.linux.org.uk Errors-To: cpufreq-bounces+glkc-cpufreq=m.gmane.org+glkc-cpufreq=m.gmane.org@lists.linux.org.uk Content-Type: text/plain; charset="us-ascii" To: cpufreq@lists.linux.org.uk -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 what's happening exactly? I had tested AMD Athlon64 (Winchester core) and found out how PowerNow controls Vcore. I've been manualy overriding Frequency/Voltage pairs on it to undervolt it in both 1.8 and 1.0GHz states. Is it the same with Intel SpeedStep? If it's the same, this scenario would be right: CPU boots with Vcore that is set in the BIOS. SpeedStep reads Frequency(Multiplier)/Vcore table from BIOS and uses it. E6300 @ default: 7 x 266MHz (1.86GHz) ~1.35V on the full load 6 x 266MHz (1.60GHz) ~1.15V in the idle state so, if I raise FSB to 400MHz I get: 7 x 400MHz (2.80GHz) ~1.35V on the full load 6 x 400MHz (2.40GHz) ~1.15V in the idle state So, my CPU has to be stable in both situations: 2.8GHz @1.35V and 2.4GHz @1.15V Guess it's the main "stability" problem if SpeedStep is on while overclocking. Guess it's more difficult to get it run stable @1.15V with mulitplier 6 than @1.35V with multiplier 7. Another thing: If I raise Vcore to ~1.45V in the BIOS, and set some high CPU freq that can not be achieved with ~1.35V, when SpeedStep kicks in it will read Multiplier/Vcore table from BIOS and NOT Vcore I've set manualy. So, it will use 1.15 and 1.35V for multiplliers 6 and 7 and bring instability on that high frequencies. So, anyone with Intel Core 2 Duo, is the process the same ? -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGiHMqqDH2e5UXzrQRAq1TAJ4xAsFbynDDNYfQP7nXsG6fq8cTxgCfRFBX f9eem+XAKPUsWNIncEomxpY= =YOe9 -----END PGP SIGNATURE-----