CRANS-MONTANA, September 5, 2014 (AFP) - The Scot added a 66 to his opening 62 for a halfway total of 12 under par at the picturesque Crans Montana course, one ahead ahead of Donaldson who added a 64 to his opening 65.
American Brooks Koepka is a shot further back after consecutive rounds of 65, alongside England's Graeme Storm, who carded a 66.
"Today was a little bit tougher, especially on the back nine, where some of the pins were very tricky," said Ramsay, who had shared the overnight lead with Italian Edoardo Molinari.
Molinari dropped four shots off the pace with a level-par 70 in early wet conditions.
"The rain made life a bit trickier and the temperature also dropped, which made distance control difficult," said Ramsay.
"So it was definitely harder than yesterday, but I stayed steady and my attitude was good again, so overall it was another good day's work."
Ramsay looked like enjoying a two-shot lead until Donaldson completed a 64 with a seventh birdie of the day.
"I played well again today, especially on the front nine," said Donaldson, who is seeking back-to-back wins after victory in the Czech Masters sealed his place on the European team for Gleneagles.
"There are birdies to be had, but you have to play really aggressively and then you run the risk of getting yourself into trouble.
"It's a very fair course, but it's also a real test in places so you have to stay patient and not go too gung ho."
Koepka, 24, carded eight birdies and three bogeys, one of the dropped shots coming when his drive finished just a few feet out of bounds on the short seventh.
Fellow-American David Lipsky was a shot behind on nine-under, alongside Ireland's Shane Lowry and Northern Ireland's Gareth Maybin.
Donaldson's Ryder Cup team-mate player Victor Dubuisson was four shots off the pace after recovering from a double bogey on the 12th, his third hole, to return a 67.
Second round scores from the EPGA European Masters at the par-70 Crans Montana course on Friday (GBR & IRL unless stated):
128 - Richie Ramsay 62-66
129 - Jamie Donaldson 65-64
130 - Brooks Koepka (USA) 65-65, Graeme Storm 64-66
131 - Gareth Maybin 64-67, Shane Lowry 66-65, David Lipsky (USA) 67-64
132 - Victor Dubuisson (FRA) 65-67, Marc Warren 69-63, Tommy Fleetwood 64-68, Seve Benson 65-67, Edoardo Molinari (ITA) 62-70
133 - Tyrrell Hatton 67-66, Robert Jan Derksen (NED) 66-67, Peter Whiteford 68-65, David Lynn 65-68, Michael Hoey 65-68
134 - Emiliano Grillo (ARG) 66-68, Peter Hanson (SWE) 66-68, Brett Rumford (AUS) 69-65, Felipe Aguilar (CHI) 66-68, Wade Ormsby (AUS) 67-67, Raphael Jacquelin (FRA) 65-69
135 - Matthew Nixon 66-69, Richard Green (AUS) 71-64, Nicolas Colsaerts (BEL) 68-67, Julien Quesne (FRA) 69-66, James Morrison 66-69
136 - Craig Lee 66-70, Soren Hansen (DEN) 69-67, Matthew Baldwin 68-68, Rikard Karlberg (SWE) 68-68, Lee Slattery 68-68, Adrien Saddier (FRA) 69-67, Jamie McLeary 66-70, Chapchai Nirat (THA) 66-70, Bernd Wiesberger (AUT) 66-70
137 - Hennie Otto (RSA) 68-69, Ricardo Santos (POR) 67-70, Danny Willett 67-70, Gary Stal (FRA) 71-66, Alvaro Quiros (ESP) 69-68, Romain Wattel (FRA) 68-69, Mark Foster 69-68, Jyoti Randhawa (IND) 72-65, Padraig Harrington 66-71, Anirban Lahiri (IND) 70-67, Gregory Havret (FRA) 68-69
138 - Sihwan Kim (KOR) 72-66, Marco Crespi (ITA) 69-69, Mikael Lundberg (SWE) 67-71, Anders Hansen (DEN) 67-71, Adilson Da Silva (BRA) 73-65, Martin Rominger (SUI) 68-70, Ricardo Gonzalez (ARG) 70-68, Robert Rock 69-69, Paul Lawrie 70-68, Thorbjorn Olesen (DEN) 69-69, Thomas Bjorn (DEN) 66-72, Justin Walters (RSA) 70-68, Francois Calmels (FRA) 70-68, Nacho Elvira (ESP) 70-68, Adrian Otaegui (ESP) 68-70
139 - Rahil Gangjee (IND) 72-67, John Parry 71-68, Seuk-hyun Baek (KOR) 69-70, Mikko Ilonen (FIN) 73-66, Matteo Manassero (ITA) 68-71, Peter Lawrie 69-70, Morten Orum Madsen (DEN) 70-69, Scott Jamieson 70-69, Jose-Filipe Lima (POR) 71-68, Joachim B Hansen (DEN) 72-67, Peter Uihlein (USA) 72-67, Prom Meesawat (THA) 66-73, Bradley Dredge 70-69, Richard Bland 70-69, David Howell 69-70, Jin Jeong (KOR) 71-68, Johan Carlsson (SWE) 70-69, Jason Knutzon (USA) 70-69, David Drysdale 66-73
Failed to make the cut:
140 - Darren Clarke 74-66, George Coetzee (RSA) 74-66, Miguel Angel Jimenez (ESP) 70-70, Victor Riu (FRA) 71-69, Alexander Levy (FRA) 71-69
142 - Jose-Maria Olazabal (ESP) 70-72, Masahiro Kawamura (JPN) 68-74
143 - Thomas Aiken (RSA) 69-74, Niclas Fasth (SWE) 71-72
144 - Gregory Bourdy (FRA) 73-71, Darren Fichardt (RSA) 73-71, Digvijay Singh (IND) 71-73
145 - Jeev Milkha Singh (IND) 72-73